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CNR - Bologna Research Area
CNR - Bologna Research Area
Via Piero Gobetti 101, I-40129, Bologna, Italy
Description
Welcome to the XV ET Symposium
The XV ET Symposium will take place in Bologna from May 26th until May 30th.
The ET Symposium kicks off on Monday 26th after lunchtime and will end on Friday 30th at lunchtime.
The symposium's social dinner will take place on Wednesday 28 May. On the evening of Monday 26 May, there will be an Early Career Researcher (ECR) social event. Further details about both events can be found on the social events page.
The Symposium venue is the Bologna CNR Research Area. Information about the venue and how to get there can be found on the Venue and travel info page.
The Symposium will be organized in parallel sessions, hosting workshops managed by the ET boards (EIB, ISB, OSB, and SPB), and plenary sessions. The complete timetable is now available.
A poster session will be held on Tuesday afternoon. For presenters: the size of the poster support is 95 cm x 115 cm.
The abstract submission for talks & posters is closed.
The registration is now open. The fee for in-person participants is:
- Before April 28th (regular fee): €400 (VAT included)
- After April 28th (late fee): €500 (VAT included)
The fee includes the social dinner. In order to keep the fee as low as possible, no fee reductions will be granted. The limit for in-person attendees is 380 people.
Participants can also attend the Symposium remotely via Zoom. While registration is required, there is no fee for online participation.
Cancellation policy:
Refund requests received by April 28th will be granted in full, subject to a €50 deduction for administrative costs. No refunds will be issued for cancellations received after April 28th.
Group picture
The XV ET Symposium is organized by the Department of Physics and Astronomy "Augusto Righi" of the University of Bologna, the INFN - Bologna Division, the INGV - Bologna Division, and the INAF - Astrophysic and Space Science Observatory of Bologna.
Registration
Online registration
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Start of ET Symposium
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Plenary 0 Plenary Room
Plenary Room
Welcome by LOC & poster sparklers
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ET Mentoring Program
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Coffee break
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Instrument Science (ISB) Plenary Room
Plenary Room
Conveners: Jan Harms, Stefan Hild -
Observational Science (OSB) Rooms 215 & 216
Rooms 215 & 216
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OSB Roadmap: Div 2Speakers: Angelo Ricciardone, Archisman Ghosh (Universiteit Gent), Mairi Sakellariadou
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OSB Roadmap: Div 3Speakers: Antonio Riotto (Université de Genève), Irina Dvorkin, Michela Mapelli
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OSB Roadmap: Div 4Speakers: Andrew Levan (Radboud University), Giancarlo Ghirlanda (Istituto Nazionale di Astrofisica - Osservatorio di Brera & INFN sezione di Milano Bicocca), Susanna Vergani (LUX, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS, 92190 Meudon, France)
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OSB Roadmap: Div 5Speakers: B.S. Sathyaprakash, Monica Colpi, Dr Nicola Tamanini (L2IT / CNRS), samaya nissanke
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OSB Roadmap: Div 6Speakers: Micaela Oertel (LUTH, CNRS/Observatoire de Paris), Tania Hinderer, Tim Dietrich (University of Potsdam)
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OSB Roadmap: Div 7Speakers: Cristiano Palomba, Ik Siong Heng (University of Glasgow), Marco Limongi
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OSB Roadmap: Div 8Speakers: Harald Pfeiffer (Max-Planck-Institute for Gravitational Physics), Laura Bernard, Patricia Schmidt
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13
OSB Roadmap: Div 9Speakers: Andrea Maselli, Michal Bejger (INFN Ferrara & CAMK PAN), Michele Mancarella (Milan-Bicocca)
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14
OSB Roadmap: Div 10Speakers: Anuradha Samajdar, Elena Cuoco, Prof. Gianluca Maria Guidi, Tania Regimbau (LAPP/CNRS)
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OSB Roadmap: DiscussionSpeakers: Archisman Ghosh (Universiteit Gent), Marica Branchesi (Gran Sasso Science Institute), Michele Maggiore
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ISB / ETO Taskforce Plenary Room
Plenary Room
Convener: Fiodor Sorrentino-
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General introduction to ETO Design Task ForceSpeaker: Fiodor Sorrentino
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Optical layout updates, flexibility envelope and flexibility demands - 2L & triangleSpeakers: Anna Green (Nikhef), Antonio Perreca
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Detector layout updates - 2L & triangleSpeaker: Max Majoor
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16
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Early career social event Dragon Pub - Viale della Repubblica, 16a, 40127 Bologna BO
Dragon Pub - Viale della Repubblica, 16a, 40127 Bologna BO
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ET e-Infrastructure Board (EIB) Room 213
Room 213
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22
IntroductionsSpeakers: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco
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23
Div 3 reportSpeakers: Georgy Skorobogatov, Gonzalo Merino, Paul Laycock
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24
ET-PP WP8Speakers: Nadia Tonello (Barcelona Supercomputing Center), Oscar Reina
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25
Challenges in Multimessenger Astronomy in the ET Era: From Interoperability to Multimodal Generative AI Systems
The Einstein Telescope (ET) opens a transformative era in gravitational wave astronomy, heralding the onset of big-data-driven multimessenger exploration. In this context, the adoption of interoperable standards promoted by the International Virtual Observatory Alliance (IVOA), becomes crucial for integrating and analyzing diverse and large-scale astronomical datasets. This study proposes a novel expansion of the MOC maps. MOC is a hierarchical data structure widely recognized for efficiently encoding and visualizing sky regions, has already demonstrated success by enabling cross-matching of astronomical catalogs, multi-wavelength surveys, and facilitating the collaborative data analysis essential to multimessenger astronomy. We introduce "Textual MOCs"—which incorporate detailed textual descriptions directly into sky regions—and "Semantic MOCs," which convert these textual contents into semantic embeddings. These embeddings represent textual meaning in multidimensional spaces and are stored in optimized vector databases, enabling sophisticated analytical operations such as similarity searches and complex semantic queries. The integration of Textual and Semantic MOCs substantially enhances sky maps by embedding rich contextual information and semantic insights, improving user engagement, and enabling the development of interactive and educational tools. Additionally, incorporating multimodal generative artificial intelligence systems further refines the analytical capabilities, supporting context-aware interactions, and enhancing accuracy in spatial, semantic, and visual operations. The seamless interoperability provided by adherence to IVOA standards ensures broad accessibility, facilitating global collaboration, and significantly advancing multimessenger astronomical research in the era of ET.
Speaker: Giuseppe Greco -
26
Update on the CTLab4ET deployment
The CTLab4ET (Computing Technology Laboratory for ET) is one of the laboratories funded by the ETIC (ET Infrastructure Consortium) project. Its purpose is to provide the ET Collaboration with a playground where the most recent computing technologies can be tested and benchmarked. Since ET will become operational in about ten years and computing software and hardware evolution is very fast, it is mandatory to keep up with the latest available possibilities in this field and to be able to make an educated guess on their status at the time they will be used. Moreover, by the end of 2025, the first draft of the ET computing model is expected and this requires a careful evaluation of the computing needs and desiderata for a successful and efficient operation of the experiment. These are the reasons why a laboratory such as CTLab is necessary for ET Preparatory Phase and for ET R&D in general.
The procurement of the machines was completed last year and the implementation of the management layer is in progress: it foresees the setup of a Kubernetes cluster with different access models, with a system of authorization/authentication based on ET IAM AAI. It will be tested and further developed to adjust to the community needs during Mock Data Challenges. In this contribution, a description of the laboratory, inaugurated on April 14th 2025, will be given, focusing on the available hardware infrastructure and describing the software framework which is under implementation to make the cluster available for the collaboration.Speaker: Lia Lavezzi (INFN Torino) -
27
GW data analysis on the ESCAPE Virtual Research Environment
I will present the ESCAPE Virtual Research Environment (VRE), focusing on how an R&D gravitational wave pipeline, the Wavelet Detection Filter (WDF) can be run entirely in the ESCAPE Virtual Research Environment (VRE). The ESCAPE VRE is a modular, scalable platform to streamline scientific analysis, minimizing software environment setup and data discovery times. It is composed of an authentication and authorization infrastructure (AAI) layer and a customizable jupyterhub interface with pre-loaded environments. Data can be accessed on the VRE leveraging the Rucio distributed data management solution. The presentation will guide the user through the individual steps to run the WDF pipeline, from authentication, to data discovery and analysis reproducibility.
Speaker: Dr Alberto Iess (CNRS LAPP) -
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Discussion
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Instrument Science (ISB) Plenary Room
Plenary Room
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29
E-test Update
E-TEST is a low-frequency suspension prototype developed for the Einstein Telescope, featuring a 100-kg test mass cooled to cryogenic temperatures (20–25 K) through radiative cooling techniques. The prototype is designed to provide compact seismic isolation at low frequencies (<10 Hz) while minimizing thermal noise, addressing the critical noise sources for next-generation gravitational-wave detectors. It is experimentally actively isolated, with promising results in suppressing seismic disturbances at low frequencies. In addition, cryogenic sensors and electronics are integrated to monitor vibrational motion in the penultimate cryogenic stage. E-TEST serves as a crucial R&D platform for advancing suspension technologies and defining the technical design for the Einstein Telescope.
Speaker: MOUHAMAD HAIDAR LAKKIS (University of Liege, Université Libre de Bruxelles) -
30
New Generation Superattenuators (NGSA) for Einstein Telescope: status of the projet
The 3rd generation instrument era is approaching, and the Einstein Telescope giant interferometer is becoming a reality with the possibility to install the detector in an underground site where seismic noise is 100 times smaller than on surface. Moreover, new available technologies and the experience acquired in operating advanced detectors are the key points to further extend the detection bandwidth down to 2-3 Hz with the possibility to suspend a cryogenic payload. NGSA is an R&D project, involving the Napoli, Pisa and Sassari ET groups, based on the improvement of vibration isolation performance for 3rd generation detectors of Gravitational Waves ‘Einstein Telescope (ET)’. Starting from the present mechanical system of the Advanced VIRGO interferometer (2nd generation), considered compliant with 3rd generation detector, we studied the possibility of improving the attenuation performance. This has been done with a multistage pendulum chain equipped with new magnetic anti-springs that is hung to a double Inverted Pendulum in nested configuration (NIP). The main outcoming goal is the construction and test of a NIP prototype in the “PLANET” laboratory in Naples. In this talk, we present the status of the NGSA project pointing out the impact of two seismic isolation system solutions, with different heights, on the sensitivity of ET-LF interferometer. In addition, the status of the NIP prototype construction will be reported.
Speaker: Lucia Trozzo -
31
The status of CAOS laboratory
The CAOS (Center for Applications on Gravitational Waves and Seismology) laboratory, part of the ETIC (Einstein Telescope Infrastructure Consortium) project, represents a significant Italian initiative designed for advancing third-generation gravitational wave detector technologies. CAOS has been envisioned as a hub for collaborative innovation and testing, particularly focusing on the next-generation suspension chains for the Einstein Telescope.
Currently under construction in Perugia, the laboratory will feature two 15-meter vacuum towers equipped with superattenuators to realize a seismic isolated Fabry-Perot cavity. There is also potential for incorporating a third tower to accommodate an interferometer in the future.
This presentation will provide an overview of the infrastructure’s current status, highlight some initial studies, and discuss forthcoming developments concerning the construction, the vacuum towers, and the superattenuators.Speaker: Francesco Bianchi (INFN-Perugia) -
32
COBRI Sensor development for seismic isolation and control
Current gravitational wave detectors are limited at frequencies below 10 Hz by sensing and control noise related to the active seismic isolation systems and their local displacement sensors.
In order to overcome these limitations, the use of new, more accurate local displacement sensors, has been proposed.
In this talk I present our current design for a compact local displacement sensor based on “Deep-Frequency modulation interferometry” and show the infrastructure and performance of our first build "Compact Balanced Readout Interferometer (COBRI)" prototype.
The COBRI features a quasi-monolithic component including all optics (expect the target mirror) in a compact setup, which is connected to a custom build amplifier and a MTCA based phasemeter. The phasemeter runs a newly developed (analytic) readout algorithm to extract the signal parameters, implemented in an FPGA, enabling a close to optimal precision and a high readout bandwidth.Speaker: Tobias Eckhardt -
33
Static Fatigue in Fused Silica Fibres
Fused silica fibres used in current ground-based gravitational wave detectors, such as Advanced LIGO, sustain loads of 40 kg with stresses reaching up to ~780 MPa in their thinnest regions. Reducing fibre diameter and increasing stress improves suspension thermal noise performance by improving damping dilution. In addition, the resonant modes are shifted to more favourable frequency ranges within the detection band by raising the violin mode and lowering the bounce and roll mode frequencies. Future detectors, such as Cosmic Explorer and Einstein Telescope HF, aim to operate at higher stresses, however, fibre lifetime under a static load is limited by failure due to surface or volumetric defects.
Hang times of fibres under a constant stress have been previously measured in air indicating lower lifetimes due to stress-enhanced reactions with atmospheric moisture. Preliminary tests done at the Institute for Gravitational Research, Glasgow show that fibres held at 4.4 GPa lasted only 22 seconds in air but exceeded 77 days when loaded in vacuum. Since the fibres support expensive optics which are not easily replaceable, accurately estimating fibre lifetime under vacuum at operational stress levels is essential for defining safe design stresses while optimizing thermal noise performance.
Since direct testing at design stress would require multi-year experiments, we test fibres at higher stresses with reasonably small lifetimes and extrapolate to operational values using empirical models based on crack propagation mechanics. Additionally, we will use spectrometry to determine the vacuum exposure time required for moisture outgassing before it is safe to load the fibres.
Speaker: Varun Deshmukh (Institute for Gravitational Research, University of Glasgow) -
34
Mechanical Oscillators in Non-Equilibrium Thermodynamics (MONET)
To reach higher sensitivities in the frequency band below 10 Hz in third generation terrestrial gravitational wave detectors, such as the Einstein Telescope, the individual noise sources must be addressed and their impact on the system reduced. One of these noise sources is thermal noise, to be addressed through operating ET at cryogenic temperatures.
The cooling of the detector will introduce a temperature gradient along the suspensions at which the optical components are located. It is crucial to understand and characterise any effect of this thermal gradient onto heat dissipation and therefore the mechanical behavior of the suspensions. This behavior is complex, and current models, based on the fluctuation-dissipation theorem, do not capture all aspects of it creating the need for experimental work toward understand these effects.
The "Mechanical Oscillators in Non-Equilibrium Thermodynamics (MONET)" project aims to investigate, define and quantify the changes in mechanical properties of a suspension when a temperature gradient is introduced to a system along the suspension. To explore this, we use an experimental setup, where a mirror is suspended on thin wires, along which we create a temperature gradient of up to 60 K. To monitor the changes to the mechanical properties of the suspension, we used a high dynamic range interferometer, based on homodyne quadrature interferometry.
In this contribution, we will present the results of the experimental work, its conclusions and limitations, outlining the next steps towards better understanding of thermal noise is such systems, and through this reaching higher sensitivities in cryogenic detectors.
Speaker: Wanda Vossius (Helmut Schmidt University Hamburg) -
35
DESIGN AND ANALYSIS OF A CRYSTALLINE SILICON TRIANGULAR VERTICAL SPRING BLADES-CRYOGENICS SUSPENSION SYSTEM FOR THE EINSTEIN TELESCOPE
This study focuses on optimizing crystalline silicon triangular blade springs for the vertical suspension system of the Einstein Telescope (ET) to enhance cryogenic performance. By leveraging silicon’s high Q-factor and thermal conductivity, the design minimizes thermal noise and ensures efficient heat dissipation at low temperatures. Structural integrity is improved through material selection and flexible joints, reducing thermal stress and mechanical mismatches. The blades are optimized for vibration isolation, ensuring precise alignment and stability. Using ANSYS simulations and Finite Element Analysis (FEA), key parameters like length, width, and thickness are refined, while experimental validation via wire electrical discharge machining (WEDM) confirms simulation predictions. A dual-load approach examines the impact of crystalline orientations, enhancing design flexibility. The results highlight potential improvements in noise attenuation, contributing to future advancements in precision instrumentation and gravitational wave detection.
Speaker: Esra Zerina Appavuravther -
36
A single-cavern solution for the ET-LF test-masses
The test-masses for ET-LF present one of the most complex hardware design challenges in the whole project. We propose a conceptual design for the towers that is capable in principle of addressing several concerns: rigid mounting of the suspension system; interfaces with the cryogenic and cryogentic vacuum systems; and clean installation and access. The design simplifies the civil-infrastructure interface, operating in a single cavern without underfloor excavation. There are many complex design issues still to address, but there do not appear to be any technological show-stoppers.
Speaker: Conor Mow-Lowry (Vrije Universiteit Amsterdam)
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29
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Observational Science (OSB) Rooms 215 & 216
Rooms 215 & 216
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37
Theory-agnostic searches for non-gravitational modes in black hole ringdown
In any extension of General Relativity (GR), extra fundamental degrees of freedom couple to gravity. Besides deforming GR forecasts in a theory-dependent way, this coupling generically introduces extra modes in the gravitational-wave signal. We propose a novel theory-agnostic test of gravity to search for these nongravitational modes in black hole merger ringdown signals. To leading order in the GR deviations, their frequencies and damping times match those of a test scalar, vector, or tensor field in a Kerr background, with only amplitudes and phases as free parameters. This test will be highly valuable for future detectors, which will achieve signal-to-noise ratios higher than 100 (and as high as 1000 for space-based detectors such as LISA). By applying this test to GW150914, GW190521, and GW200129, we find that the current evidence for an extra mode is comparable to that for the first gravitational overtone, but its inclusion modifies the inferred remnant spin.
Speaker: Francesco Crescimbeni -
38
Echoes of the black hole microstructure
The LIGO-VIRGO-KAGRA observations are so far compatible with the Kerr black hole paradigm, though they cannot rule out entirely the existence of black hole mimickers. These are ultra-compact objects that reproduce some observable properties of black holes, while possibly predicting characteristic signatures such as non-trivial tidal deformability and/or repeated gravitational wave echoes in the ringdown.
An interesting example is offered by ``topological stars”: regular and horizonless solutions to five-dimensional Einstein-Maxwell theory, which resemble static BHs upon reduction to four dimensions. Apart from providing a viable mimicker candidate that arises from a relatively simple theory, these compact objects can also be regarded as a classical toy model of quantum black hole microstates.
In this talk we will present our latest results concerning the linear response of topological stars, with a focus on their characteristic spectrum, gravitational wave echoes and (linear) stability.
Speaker: Alexandru Dima (Università Sapienza di Roma) -
39
Environmental imprints on black hole ringdowns: quasinormal modes in matter halos
Black hole spectroscopy offers insights into the properties of black hole remnants. However, most models assume idealized, vacuum spacetimes, neglecting the astrophysical environments in which black holes reside.
Our most recent results show that the presence of matter halos, such as dark matter distributions, affects the quasinormal modes (QNMs) of black holes. We examined black holes embedded in a variety of matter profiles, including Hernquist and Navarro-Frenk-White distributions.
Our analysis shows that the surrounding environment leads to a universal redshift of QNM frequencies and damping times, proportional to the halo’s compactness. In this talk I will describe the numerical techniques used to construct these black hole spacetimes and compute their QNMs, and discuss the implications of these findings for gravitational wave observations with next-generation detectors like LISA and the Einstein Telescope.
Speaker: Laura Pezzella (GSSI, INFN) -
40
Model-agnostic inspiral tests of the multipolar structure and tidal properties of a Kerr Black Hole
The groundbreaking discovery of Gravitational Wave (GW) astronomy in the past decade has significantly advanced our understanding of the gravitational interaction in extreme gravity environments. One of the key scientific goals of future ground-based GW detectors like the Einstein Telescope (ET) is to test Einstein’s theory of General Relativity (GR) and explore the nature of GW sources, such as compact objects; holding extraordinary potential for breakthroughs in astrophysics, cosmology, and fundamental physics.
This work mainly focuses on a test of gravity in the extreme regime, more precisely on a forecast for parametrized deviations to the inspiral phase of the GW signal emitted by compact binary coalescing systems as predicted by GR. Several Parameter Estimation (PE) codes tuned toward future detectors, such as gwfish, are based on the Fisher Information Matrix formalism and designed to investigate and compare the PE capabilities of different detector networks. The main goal of this project is to evaluate statistical constraints expected from ET on possible modifications to GR, exploiting and generalizing gwfish. Beginning with state-of-the-art GR templates, such as TaylorF2, we explore model-agnostic deviations from the multipolar structure and tidal properties of a Kerr black hole predicted by GR.
By leveraging gwfish flexibility in terms of detector network simulations, we explore how the predicted constraints from ET can improve by roughly an order of magnitude compared to even anticipated future interferometers, such as Advanced LIGO in its fifth observing run, and the results with the 15 km-2L configuration are better than those with a 10 km-triangular configuration by a factor of a few. Additionally, to ensure confidence in our results, we compare them to a parallel full Bayesian analysis performed with bilby, and we investigate the ET capability of breaking correlations among parameters, or parametrized GR deviations, entering the GW phase.Speaker: Alessandro Agapito -
41
Greybody factors as robust gravitational observables: insights into post-merger signals and echoes from ultracompact objects
The quasinormal mode spectrum plays a crucial role in modeling post-merger ringdown signals in binary coalescences, encompassing both black holes and ultracompact horizonless objects. However, quasinormal modes are highly sensitive to small deformations of the system and only describe the linear response within a limited and imprecisely defined timeframe after the merger. Motivated by a recently discovered connection between greybody factors and post-merger black hole signals, we study the robustness of greybody factors as gravitational observables, furnishing a complementary approach to quasinormal modes. We show that greybody factors are stable under small perturbations and unaffected by specific ambiguities that undermine the reliability of the quasinormal modes. We demonstrate that greybody factors play a significant role in characterizing also the signals emitted by wormholes and other horizonless ultracompact objects. The greybody factors of ultracompact objects exhibits both low-frequency resonances and high-frequency, (quasi-)reflectionless scattering modes. We show that these high-frequency (quasi-)reflectionless scattering modes, rather than low-frequency resonances, are directly responsible for the echoes observed in the time-domain response of ultracompact objects or black holes surrounded by matter fields localized at large distances. Our study is focused both on non-rotating and rotating solutions.
Based on: https://arxiv.org/abs/2406.01692, https://arxiv.org/abs/2501.16433, forthcoming works.
Speaker: Romeo Felice Rosato (Sapienza Università di Roma & INFN) -
42
Intermediate mass black holes play hide-and-seek
Binaries of intermediate mass black holes (IMBHs) with masses $M_{\rm bh}=10^2-10^4 M_\odot$ are predicted to emit gravitational waves (GWs) potentially detectable with the Einstein Telescope. Though IMBHs of these masses are widely expected theoretically (and likely hosted in the centre of globular clusters and dwarf galaxies), these objects are very elusive and hard to detect with methods based on electromagnetic radiation. I will present results of state-of-the-art dynamical modelling that allowed us to put 3sigma upper limits on the mass of putative central IMBHs in the globular cluster 47 Tuc ($M_{\rm bh} < 578 M_\odot$) and the dwarf spheroidal galaxy Leo I ($M_{\rm bh} < 6.8\times 10^5 M_\odot$). Nuclear star clusters (NSCs), high-density central stellar systems observed in galaxies of different morphological types, are favourable sites for IMBH binary formation and coalescence. I will explore this scenario by presenting a dynamical analysis of the $z=1.4$ gravitationally-lensed star-forming Sparkler galaxy, known for hosting a remarkable population of $10^6-10^7M_\odot$ stellar clumps. I will show that, before $z=0$, up to seven of these clumps might spiral into the galactic centre and form an NSC: if these clumps contain IMBHs, the latter might form binaries and reveal themselves emitting GWs on their way to coalescence.
Speaker: Carlo Nipoti (University of Bologna) -
43
Seeds to success: growing heavy black holes in dense star clusters
Dense stellar clusters provide ideal conditions for the formation of intermediate-mass black holes (IMBHs), i.e. heavy black holes with masses between 100 and 100,000 solar masses. These objects may arise from (i) runaway stellar collisions in light and compact clusters, or (ii) hierarchical binary black hole (BBH) mergers within massive and dense clusters. Assessing the efficiency of both processes remain computationally challenging for N-body / Monte Carlo codes either due to (i) the sheer number of models required to define statistically robust results or (ii) to the huge number of stars composing the cluster.
Semi-analytic population synthesis codes offer an efficient and new alternative to exploring IMBH formation in such environments. In this talk, I will present results from simulations of over 10 million BHs in young, globular, and nuclear clusters at various metallicities performed using the semi-analytic code B-POP. I will identify which cluster conditions favor IMBH formation, discuss how formation timescales relate to the IMBH host properties, and examine possible overlaps with IMBH observations at both low and high redshifts. Finally, I will overview potential implications of IMBH formation in our Galaxy and possible gravitational wave (GW) signatures of their production in massive clusters.Speaker: Lavinia Paiella (GSSI) -
44
Probing the population of pop III remnants using gravitational wave observations
The properties of the first stars in the Universe, known as Population III (Pop III) stars, and their remnants are still poorly understood. However, the increased sensitivity of next-generation gravitational wave observatories offers the potential to detect mergers of these early compact binaries at redshifts greater than 15. A fraction of these detections will be loud enough, that is, the signal-to-noise ratio greater than 20 in the third-generation gravitational wave detector network, and are suitable for accurately understanding the astrophysical processes behind the formation and evolution of these very first compact binaries in the Universe. Using parametric population models, we explore the detectability and parameter inference accuracy of the early Universe binary black hole populations and determine the astrophysical population properties, such as the mass, spin and redshift distributions. Furthermore, we assess the gravitational wave network requirements necessary to differentiate the properties of compact binary populations in the early Universe from those in the present-day Universe.
Speaker: Krishnendu Naderi Varium (University of Birmingham) -
45
Simulating intermediate-mass black holes in the first star clusters
Population III (Pop. III) stars are ideal candidates for the formation of intermediate-mass black holes (IMBHs, $m = 10^2-10^5\,\rm M_{\odot}$) due to their small mass loss and top-heavy initial mass function. On the other hand, the masses of these IMBHs are typically limited to a few hundred solar masses, restricting their potential as massive black hole seeds. Star cluster dynamics can overcome this limitation, and significantly enhance IMBH growth to higher masses (up to $10^4\,\rm M_{\odot}$). This occurs through both runaway stellar mergers and hierarchical binary black hole (BBH) mergers, leading to the formation of increasingly massive black holes. In my talk, I will explore the properties of BBHs and IMBHs in Pop. III star clusters forming at $z>15$. To simulate these clusters, I used the N-body code PeTar-bseEmp, a state-of-the-art tool that accurately models star cluster dynamics within an external potential while integrating single and binary stellar evolution. I will show how the mass and density of the simulated clusters, and their subsequent evolution, have a significant impact on the formation channels and features of massive black hole seeds. Finally, I will examine the role of star cluster mergers in enhancing the binary black hole merger rate and driving the growth of central IMBHs.
Speaker: Benedetta Mestichelli (Gran Sasso Science Institute) -
46
Disentangling the formation channels of binary black holes
In the last years, gravitational wave detectors proved for the first time the existence of binary black hole mergers. Investigating their formation history can give us an useful insight on poorly constrained binary interaction processes. For instance, the properties of the binary black hole population are heavily influenced by the stability and efficiency of mass transfer events, since unstable mass transfer can reduce the orbital separation by several order of magnitudes, facilitating a merger by gravitational wave emission but also increasing the risk to have a premature coalescence between the two objects. Recent detailed modeling of the stellar and binary physics involved in mass transfer events indicated that the standard prescriptions adopted for mass transfer stability were likely understimating the number of binary black holes formed through stable mass transfer evolution. In my work, I used detailed modeling and population-synthesis simulations (MESA and SEVN softwares) and showed that caution must be taken when different mass transfer models are compared. Changes in the input stellar physics, in the mass transfer prescription or in the tidal model can have similar effects in selecting the final binary properties and formation channels. Being able to disentangle between stellar evolution, mass transfer and tidal effects is crucial to correctly interpret the population of binary black hole mergers.
Speaker: Erika Korb (Università di Padova - INFN)
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37
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Site Preparation & Characterization (SCB) Room 409 at INAF-OAS
Room 409 at INAF-OAS
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09:00
Welcome to SCB session - overview
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47
Status Update of Sardinia Activities
A variety of activities are currently being carried out at the Sos Enattos candidate site, encompassing systematic local noise monitoring, identification and characterization of potential noise sources, as well as engineering and geotechnical investigations. This presentation aims to provide an updated overview of the ongoing research efforts in Sardinia.
Speaker: Davide Rozza (University of Milano-Bicocca & INFN-MIB) -
48
Overview of subsurface characterization at the EMR site
A general high-level overview is presented of the subsurface feasibility studies at EMR. Following a successful borehole campaign in 2024, a seismic campaign is about to finish, adding valuable complementary information to the core logs. A hydro-geological model is being constructed integrating water flow and pressure tests throughout the region. A noise measurement network consisting of surface and subsurface sensors is becoming operational. A second borehole campaign has just started and focus is shifting towards an integration of all data to de-risk the subsurface. A status of deliverables is presented as well as a timeline for the remaining work to complete the feasibility evaluations.
Speaker: Wim Walk (Nikhef) -
49
Updates on site characterization at the proposed Lausitz, Saxony, ET candidate site
In August 2024, the Free State of Saxony officially declared its support for the ET site location bit for building the Einstein Telescope in the Lausitz (eng. Lusatia) region. The basement of this region is formed by the Lausitz Granodiorite Massif. The regional extent of the granodiorite is not known for certain, and recent observations contradict the historic geological maps in some locations. To test whether the granodiorite is a suitable host with properties benefiting ET, a large geophysical/geological survey is currently being conducted. This survey aims to produce a high-resolution 3D model of the massif and to study the regional seismic noise conditions.
Since 2021, two seismometers in a borehole doublet and one surface broadband seismometer have recorded seismic activity within the center of the target area near the town of Cunnewitz. We compare the seasonal variations and spectral footprint at the surface with those measured in the subsurface. Eight additional boreholes are currently being prospected and drilled and will be instrumented with broadband seismometers as they are completed.
We conducted a 15 x 15 km large seismic array deployment consisting of 191 short-period and 8 broadband stations in the target region, which have been used to construct the shallow S-Wave velocity structure. This deployment will be renewed towards the east to cover the full target region of the ET. Furthermore, 100 short-period stations were deployed in January/February 2025 to characterize the annual changes in the seismic noise. Additional active seismic experiments and reflection/refraction experiments have been carried out to characterize the seismic properties. These results are compared with in-situ measurements at the boreholes and in the lab.
In this talk, I will give an overview of the current status of the project, ongoing measurements, and planned work in the near future. I will highlight the results of the local ambient noise study, active seismic lines, borehole core analysis, the development of a combined geological model, and simulations of the ambient noise field at the surface and at depth.Speaker: Prof. Andreas Rietbrock (KIT) -
50
Field hydrogeology characterization campaign in EMR
The work carried out in in the candidate site for the Einstein Telescope in the EMR to characterise the functioning of deep groundwater, and its quality will be presented. Particular attention will be paid to new piezometric measurement campaigns, the interpretation of hydraulic tests in boreholes and groundwater sampling campaigns. First data and interpretation will be presented. Future works on the hydraulic characterisation of fault zones will also be discussed.
Speaker: Daniel Drimmer (Tractebel) -
51
Groundwater modelling : new results and future works
The regional 3D model simulating groundwater flows in the candidate site for the Einstein Telescope in the EMR has been updated to better represent the interactions between the underground environment and the tunnels of the future telescope. The mesh around the tunnels has been refined and the injected zone around the tunnel modelled. The new results in terms of flows to be drained and impacts on water levels will be presented. The results of the sensitivity study will also be discussed. Future modelling work on a local scale will also be presented.
Speaker: Quentin Guillemoto (ULiège) -
52
Ultrasound transmission measurements on core samples
Ultrasound transmission measurements on core samples done at Delft University are presented. These measurements include CT-scans of plugs and the matrix density was determined with a pycnometer. Most of the samples are from ETB boreholes, but a few are also from the DZA01 borehole close to Cunnewitz, i.e. Lausitz. (Abstract to be updated later).
Speaker: Marc Boxberg (RWTH)
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09:00
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Coffee break
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ET e-Infrastructure Board (EIB) Room 213
Room 213
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The ET Members Database
The ET Members Database (ETMD) serves as the authoritative membership source for the ET Collaboration and is used in the on-boarding and off-boarding of member accounts and in the composition of specific, dedicated mailing-lists, including the Collaboration-wide list. The application is used to track Collaboration member Full-Research-Time Equivalent (FRTE) commitments to Board and Division activities; provides tools to allow Research Unit (RU) Leaders to understand quickly and easily the areas in which members of their RU are committed; details the history of the different roles within the Collaboration; and provides a range of statistical information, displaying the composition of the Collaboration from different perspectives. The ETMD has also recently been used to construct the Blue Book author list and will form part of the efforts to build the author list more generally, while it is also one of the key components in the ET Identity and Access Management project. This presentation will provide an overview of the functionalities of the ET Members Database and explain its operational aspects and where they sit in the wider workflow related to identity management in the Collaboration, while also exploring future developments.
Speaker: Gary Hemming - 54
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Discussion
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53
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ISB / ETO Project Office Plenary Room
Plenary Room
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A proposition of scheduling methodology for ETSpeaker: Christian Olivetto
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ET's Model-Based Systems Engineering exercise update: Towards a Unified Systems ArchitectureSpeakers: Frederik Moers, Romano Meijer (Nikhef)
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Risk management critical role. Risk assessment status and risk management evolutionSpeaker: Ghada Mahmoud
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Observational Science (OSB) Rooms 215 & 216
Rooms 215 & 216
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60
Postmerger: a new and dominant contribution to the gravitational-wave background from binary neutron stars
The stochastic gravitational-wave background (SGWB) generated by the inspiral and merger of binary neutron stars is traditionally modelled assuming that the inspiral is promptly followed by the collapse of the merger remnant to a rotating black hole. While this is reasonable for the most massive binaries, it is not what is expected in general, where a remnant is produced and may survive for up to hundreds of milliseconds and radiate an amount of energy that is significantly larger than that lost during the whole inspiral. To account for this additional contribution to the SGWB, we consider a waveform model that includes both the inspiral and the postmerger emission. We show for the first time that for a large set of parameterized equations of state compatible with observational constraints, there is typically five times more power spectral density in the SGWB from the postmerger emission than from the inspiral one, leading to a normalized GW energy density ΩGW ~ 10-10-10-9. This power is predominantly located in the 1-2 kHz frequency range and hence distinct from that associated with the inspiral only. We discuss the significantly enhanced detectability of the SGWB with special attention to third-generation detectors, such as the Einstein Telescope and Cosmic Explorer, and show how it depends on the signal-to-noise ratio of foreground binaries and on the metastable remnant survival time. Interestingly, even a non-detection of the high-frequency part of the SGWB could provide valuable constraints on the remnant lifetime, offering novel insights into the postmerger dynamics and into the equation of state of nuclear matter.
Speaker: Léonard Lehoucq (CNRS, Institut d'Astrophysique de Paris) -
61
Unravelling the nature of intermediate-mass black holes with ET and 3rd generation detectors
Intermediate-mass black holes (IMBHs) are elusive objects that may link stellar mass and supermassive BHs. Scarce observational evidence and theoretical uncertainties make IMBH mysterious objects whose nature represents an open question of modern astrophysics. If IMBHs form, as supported by the theoretical panorama, through interactions and collisions of stars and stellar BHs, they could be detected as intermediate-mass ratio inspirals (IMRIs) with future detectors. In this talk, I present a model simulating the formation of stellar BH binary mergers (BBHs) and IMBHs in different environments. We set the model parameters to reproduce the properties of currently observed BBHs and obtain a reliable population of IMRIs. We then characterise the detection prospects of such IMRIs with ET, LISA, and the LGWA, showing how a synergy among these detectors could constrain the nature of IMBHs.
Speaker: Manuel Arca Sedda -
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The Formation of Early Supermassive Black Holes and Their Gravitational Wave Signatures
The rapid formation of supermassive black holes (SMBHs) in the early universe (z > 6) remains one of the most significant mysteries in the Universe. Observations of SMBHs with masses reaching ~ $10^{10} M_{\odot}$ within the first billion years challenge our understanding of black hole (BH) formation and growth. Despite significant insights from the James Webb Space Telescope (JWST), the mechanisms driving this rapid evolution remain uncertain. In this study, we apply the Cosmic Archaeology Tool (CAT), a semi-analytical model, to simulate the coevolution of galaxies and their central BHs from redshift 24 to 4. CAT explores BH growth via multiple accretion processes, including Eddington-limited accretion at the Bondi-Hoyle-Lyttleton (BHL) rate, as well as super-Eddington accretion triggered by a slim disk during gas-rich galaxy mergers. The model also adopts diverse BH seeding scenarios—ranging from light to medium to heavy seeds—and tracks the formation of binary black holes (BBHs) through dynamical friction and gravitational wave (GW) emission.
A key focus of this research is the GW signatures of BBH systems and their potential detection by next-generation observatories. Advanced ground-based detectors like the Einstein Telescope (ET) and space-based interferometers such as the Laser Interferometer Space Antenna (LISA) and the Lunar Gravitational-Wave Antenna (LGWA) will enable multiband GW observations, probing intermediate-mass black holes (IMBHs) and SMBHs across different frequency ranges. LISA, operating in the millihertz band, will capture the early inspiral phase of IMBH binaries and SMBH mergers, while ET, with its high sensitivity in the decihertz to kilohertz range, will observe the later phases of IMBH and SMBH binaries, bridging the gap between space- and ground-based detectors for a comprehensive multiband GW analysis. This makes ET crucial for completing the picture of BH evolution and GW signals across different frequencies.
By comparing CAT’s predictions with upcoming GW observations, this study aims to shed light on the formation and evolution of SMBHs, offering critical insights into the early universe’s BH population and the underlying physical mechanisms governing their growth.Speaker: Nazanin Davari (INAF Observatory of Rome) -
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Exploring High-Redshift Compact Binary Evolution with Next-Generation GW Detectors
Current gravitational wave (GW) detectors are observing hundreds of binaries in the low-redshift universe, but to fully understand formation mechanisms we must probe the high-redshift regime. Next-generation detectors, such as Cosmic Explorer and Einstein Telescope, will allow us access to redshifts greater than 20, and even upgrades to existing detectors may allow us to probe the star-formation peak. In this work, we explore the capabilities of next generation observatories, and upgrades of existing GW detectors such as A#, to map the black hole and neutron star population of the Universe. In particular, we investigate the ability of different networks to accurately characterize the star formation peak at redshift 1-3. We focus on measurement of the merger rate for different populations of black holes and neutron stars and the possibility of using this information to distinguish formation scenarios.
Speaker: Divyajyoti . (LIGO Scientific Collaboration) -
64
Interface modes in inspiralling neutron stars: A smoking-gun gravitational-wave signature of first-order phase transitions
Quantum chromodynamics predicts a phase transition from hadronic matter to deconfined quarks at extreme densities, yet its exact nature remains uncertain. Neutron stars offer a unique opportunity to probe this transition, but bulk properties—mass, radius and tidal deformability—provide only indirect signatures, which require many detections to resolve and are ineffective if the discontinuity exists at lower densities. In this talk, I report on a smoking-gun gravitational-wave signature of a first-order phase transition, identifiable in a single event: the resonant tidal excitation of an interface mode. I demonstrate the detectability of this resonance using general-relativistic perturbation calculations for an ensemble of nuclear-matter equations of state informed by chiral effective field theory. The results suggest that this signature is within reach of third-generation interferometers and may even be observable with LIGO A+ in sufficiently loud events.
Speaker: Dr Fabian Gittins (Utrecht University) -
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Probing hadron-quark phase transition in twin stars using f-modes
Although it is conjectured that a phase transition from hadronic to deconfined quark matter is possible in the ultrahigh density environment in Neutron Stars, the nature of such a transition is still unknown. Depending on whether there is a sharp or slow phase transition, one may expect a third family of stable compact stars or “twin stars” to appear, with the same mass but different radii compared to Neutron stars. The possibility of identifying twin stars using astrophysical observations has been a subject of interest, which has gained further momentum with the recent detection of gravitational waves from binary neutron stars. In this work, we investigate for the first time the prospect of probing the nature of hadron-quark phase transition with future detection of gravitational waves from unstable fundamental f-mode oscillations in Neutron Stars. By employing a recently developed model that parametrizes the nature of the hadron-quark phase transition via “pasta phases”, we calculate f-mode characteristics within a full general relativistic formalism. We then recover the stellar properties from the detected mode parameters using Universal Relations in gravitational wave asteroseismology. Our investigations suggest that the detection of gravitational waves emanating from the f-modes with the third-generation gravitational wave detectors offers a promising scenario for confirming the existence of the twin stars. We also estimate the various uncertainties associated with the determination of the mode parameters and conclude that these uncertainties make the situation more challenging to identify the nature of the hadron-quark phase transition. The f-mode in neutron stars is associated with pulsar glitches which can be studied through multi-messenger observation techniques.
Speaker: David Edwin Alvarez Castillo (Institute of Nuclear Physics Polish Academy of Sciences) -
66
Stability of differentially rotating hyper-massive neutron stars
An understanding of differentially rotating relativistic stars is key to many areas of astrophysics, in particular to the emission of gravitational waves. A newly born, proto-neutron star or a compact
remnant of neutron stars binary merger are expected to rotate differentially and to be important sources of gravitational radiation. A highly accurate and stable, relativistic spectral code is used to explore the whole solution space for broad ranges of the degree of differential rotation. Staying within an astrophysically motivated range of rotation profiles, we investigate the characteristics of neutron stars with maximal mass for all types of sollution and different equations of state. We find various types of configurations, which were not considered in previous work, mainly due to numerical limitations. The maximum allowed mass for the new types of configurations and moderate degree of differential rotation can be even 2-4 times higher then the maximum mass of non-rotating neutron stars with the same equation of state. Differential rotation can temporarily stabilize a hyper-massive neutron star against gravitational collapse. I will discuss the stability properties of such stars. This result may have important consequences for the gravitational wave signal expected from coalescing neutron star binaries or from some supernova events.Speaker: Prof. Dorota Rosinska (University of Warsaw) -
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Subsolar mass compact objects
Neutron stars having a mass smaller than about 1.17 Ms cannot be produced by any “standard” astrophysical mechanism. On the other hand, the analysis of SAX J1808.4-3658 has suggested a mass of about 0.8 Ms, or smaller (Di Salvo et al. MNRAS 483 (2019) 767) and a similar mass has been obtained by the analysis of HESS J1731-347 (Doroshenko et al. Nature Astronomy 2022). Also, masses and eccentricities of Gaia binaries suggest the existence of ∼ 1 Ms NSs (Shahaf et al. MNRAS 518, 2991 (2023)).
We have shown that strange quark stars having a mass in that range can instead be produced (Di Clemente et al. Astron.Astrophys. 678 (2023) L1; Di Clemente et al. Astrophys.J. 967 (2024) 2, 159).
Even though the previous objects are not black holes, primordial black holes can also have a mass in that range. LV has not identified objects in that mass range, although a couple of mergers suggested possible candidates. We show that ET should be able to distinguish between mergers of black holes and of strange quark stars, since the estimated tidal deformability of subsolar mass strange quark stars is very large.
Speaker: Alessandro Drago (University of Ferrara)
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60
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Site Preparation & Characterization (SCB) Room 409 at INAF-OAS
Room 409 at INAF-OAS
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68
First results of the surface ambient seismic noise characterization campaign along scan-lines around Terziet.
In November 2024, the ET-EMR noise characterization team conducted a passive seismic survey in the Euregio Meuse-Rhine (EMR) region, focusing on the area surrounding the Terziet broadband seismic stations (NL.TERZ) at both surface level and a depth of 250 meters. The primary objective of this survey was to identify and characterize the dominant seismic noise sources in the region.
To achieve this, we deployed a series of scan-lines extending from various suspected noise sources—including wind turbines, bridges, tunnels, and pumping operations—measuring the surface wavefield along trajectories leading toward the Terziet borehole station. Additionally, a small seismic array with a 500-meter aperture was installed to complement the setup.
In this presentation, we will provide a general overview of the seismic noise environment and focus on a detailed analysis of one or two key noise sources. Finally, we will discuss how these findings can help establish guidelines for future surveys using a similar approach.Speaker: Hadrien Michel (ULiège) -
69
First results of the 2025 active seismic campaign at the EMR-site
Taking the experience from the 2022 drilling and seismic acquisition campaign on board the subsurface team of the EMR-regions devised a second data acquisition program that was executed from Q2 2024 to Q1 2025. The purpose of the campaign was to enable the construction of a 3D integrated subsurface model in support of civil engineering, and hydrogeological as well as seismic noise modelling.
As part of the drilling campaign four wells at potential corner points of the ET-triangle were newly instrumented with optical fiber for digital strain, temperature, and acoustic sensing (DAS). During the active campaign the DAS-fiber were used to acquire vertical-seismic-profiles (VSP’s), simultaneously with the acquisition of 2D seismic lines that connect prospective corner-points. In total some 95km of 2D data and 5 VSP’s were acquired.
The very first processing results of the 2D surface lines and VSP’s are just becoming available and show an improved near surface image. This can be attributed to some optimized acquisition parameters, while keeping the cost in mind.
The 2D surface seismic was acquired with a 4m source and receiver spacing, which allowed just an adequate sampling of the seismic wavefield. In contrast to conventional acquisition design not a group of vibrators but only one single vibrator was used. This avoided the interference noise that occurs when using multiple vibrators at the same time and likely contributes to the improved near surface image. To reduce the environmental impact and being allowed to enter ecologically sensitive areas an electrical vibrator was employed. It operated reliably between 2-120Hz at 7000N. As geophones 1-component nodes with a frequency range of 1-125Hz were deployed, to at least a maximum offset of 1200m.
For the VSP’s the vertical sampling was set at 8m being a compromise between obtaining a sufficient signal-to-noise ratio and an acceptable vertical resolution. The source spacing was again 4m. The goal of the VSP’s is, besides enabling the time-to-depth conversion of the surface seismic, to provide detailed 1D velocity and attenuation profiles, which will be useful for realistic seismic noise modelling.Speaker: Michael Kiehn (Nikhef) -
70
Ground Motion Analysis for the Einstein Telescope: ShakeMap, Seismic Hazard, and Case Studies
The Einstein Telescope (ET) project, a significant leap in gravitational wave observatories, demands an exceptionally stable environment to minimise seismic noise. To ensure the most suitable site selection, we conducted a meticulous ground motion analysis, integrating historical and recent instrumental earthquakes relevant to the area. By utilising ShakeMaps and severe ground motion measurements (e.g., Peak ground acceleration, Peak spectral acceleration at several periods), we were able to parameterise key seismic events and evaluate expected shaking patterns in a comprehensive manner.
We analysed scenarios including historical relevant earthquakes at Euro-Mediterranean scale. By comparing estimated shaking levels with European seismic hazard models, we provide a comprehensive overview of the expected ground motion at the site. These findings, which contribute to a refined understanding of site suitability for ET, are of utmost importance in ensuring optimal conditions both for the future gravitational wave observations and the long-term operativity of ET infrastructure and its duty cycle.Speaker: Licia Faenza (INGV) -
71
Seismic array analysis in the Italian candidate site for ET
We present the results of three temporary deployments of seismic arrays, installed in two vertices of a possible configuration of ET in the area of the Italian candidate site (Sardinia). The experiments, aimed at investigating the local noise sources and the seismic velocity structure, were carried out in 2021 and 2024 with different geometrical layouts, number of sensors and total recording time. In this study, we show the results primarily focusing on the noise spectral characteristics and its azimuthal distribution obtained by beamforming analysis. Moreover, we extract Rayleigh wave dispersion curves from FK-analysis, which are finally inverted to obtain a one-dimensional, shear-wave velocity profile of the subsurface.
Seismic data confirm the exceptionally low level of seismic noise for frequencies above 1 Hz, as their spectra approach the Peterson's NLNM. Regarding the noise source distribution, we are able to adequately reconstruct the seismic wavefield only in the 10-20 Hz range, showing an almost azimuthally homogenous noise source distribution for all arrays, with slowness between 0.4 and 0.5 s/km. The inversion of dispersion curves in the same frequency range highlights the presence of a rather homogeneous, high-velocity terrain (Vs = 2-3 km/s) in the first 100 m, as suggested by the local geological evidences. These characteristics of the shallow subsurface are also confirmed by the flat HVSR spectra across all arrays, thus excluding the presence of resonant, low-velocity layer at shallow depth.Speaker: Giovanni Diaferia (INGV - Sezione di Bologna)
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68
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Lunch
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Lunch meeting: Forum of National Representatives
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Instrument Science (ISB) Plenary Room
Plenary Room
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72
Upgrading the Superattenuator: Towards an Active Seismic Pre-Isolator for Next-Generation Gravitational Wave Detectors
The Superattenuator has played a pivotal role in enabling the detection of gravitational wave signals in current generation interferometers down to an unprecedented 10 Hz, attenuating the ground motion at that frequency by many orders of magnitude. For next-generation gravitational wave detectors, aiming at improving the sensitivity by more than one order of magnitude and extending the detection band down to 2-3 Hz, further improvements are necessary to push the boundaries of detection capability.
The Superattenuator seismic platform was originally equipped with piezoelectric actuators in case of necessity to compensate significant effects of ground tilt at the top stage.
One key focus in the current R&D efforts is the upgrade of the seismic platform into a six-degrees-of-freedom active pre-isolator, exploiting the piezoelectric actuators for fine-tuned active control over a wider frequency range.
In the current Superattenuator design, the actuators are mounted in a mechanical support structure suitable for heavy loads. Recently, we revised the implementation, focusing on optimizing both mechanics and control strategies, also including the possibility of addressing the horizontal degrees of freedom.
Challenges include ensuring the actuator's reliable operation in both static and dynamic modes, long-term stability, and the ability to sustain significant mechanical loads over extended periods.
Current results obtained on a testbench-sized version of a Superattenuator installed in the INFN Pisa laboratory, allowing detailed measurement of transfer functions and noise analysis, as long as a comparison with simulations supporting accurate modeling, will be presented.The lack of sensors of high enough sensitivity prevented so far active compensation for seismic motion in the very low-frequency regime.
In general, with improvements in passive and active filters, current state-of-the-art sensors will become excessively noisy.
This necessitates the development of new sensors based on principles distinct from those currently employed.
We will report on ongoing efforts on the developement of a new accelerometer, featuring a redesigned mechanical structure and optical interferometric readout, to address noise limitations in the low-frequency regime.Speaker: Francesca Spada -
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Glass sensors as an inertial sensing solution for future gravitational wave detectors
Future gravitational wave observatories require significant advances in all aspects of their seismic isolation; inertial sensors being a pressing example. Inertial sensors using gram-scale, high Q factor, glass mechanical resonators combined with compact interferometric readout are promising alternatives to kilogram-scale conventional inertial sensors. We have developed a novel technique for manufacturing glass resonators based upon wafer bonding, which removes the previous size limitations on the design of such sensors, which otherwise limited their performance. The manufacturing technique works with fused silica for room-temperature applications and is adaptable to silicon for cryogenic ones. We have produced fused silica resonators using this method and demonstrated that Q factors of over 100,000 are possible. One resonator we produced was combined with a state-of-the-art interferometric readout to form an inertial sensor. The resulting sensor was tested against other commercial, bulky inertial sensors in AEI's 10m prototype gravitational wave detector. In addition to showing the best performance demonstrated by any gram-scale sensor to date, we achieve comparable sensitivity to the significantly bulkier sensors used in gravitational wave detectors today. The scalability of the novel manufacturing method will be used to make much larger fused silica resonators, which will significantly improve future sensor sensitivity. The compact size, inherently precise calibration, and vacuum compatibility of these sensors make them ideal candidates for the inertial sensing requirements in future gravitational wave detectors.
Speaker: Jonathan Carter -
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The World’s First Underground Facility for Interplatform Control and Seismic Isolation in Gravitational-Wave Detection
We present the design and performance requirements of GEMINI, the first underground R&D facility dedicated to active seismic isolation and interplatform control for next-generation gravitational-wave observatories. The GEMINI site is located 1.4 km deep at the National Laboratories of Gran Sasso (LNGS). The facility consists of two actively isolated platforms operating in a vacuum, designed to achieve a record-low residual motion in the 1 mHz to 1 Hz band. For the Einstein Telescope (ET), GEMINI will test interplatform control in an underground environment for the first time. It will be essential in assisting the ET length and alignment control of auxiliary degrees of freedom and hence in enabling ET performance. We are also addressing the tilt-to-horizontal coupling, essential for meeting the stringent noise requirements of ET’s underground interferometers. Furthermore, GEMINI will provide platforms to test novel, high-precision accelerometers at cryogenic temperature as will be required for the Lunar Gravitational-wave Antenna.
Speaker: Tomislav Andric -
75
Magnetic Noise and Mitigation Strategies for the Einstein Telescope
Magnetic noise will pose a significant limitation on the sensitivity of future Gravitational Wave (GW) detectors, such as the Einstein Telescope (ET), especially at low frequencies from a few Hz to approximately 100 Hz. This noise primarily originates from two sources: the natural terrestrial component (Schumann Resonances) and the environmental noise associated with the interferometer (so-called self-inflicted noise). Magnetic noise arises from the coupling of environmental fields with the magnetized components of the detector. This coupling can induce both direct magnetic forces and disturbances in the control signals, ultimately contributing to noise within the detector’s sensitivity range.
Building on experience from current GW detectors, efforts have been made to identify the key contributors to magnetic noise, with the goal of optimizing these factors in the future ET infrastructure. To meet the sensitivity goals of ET, it is essential to reduce environmental fields to the level of Earth’s noise and decrease magnetic couplings by a factor of approximately 10² - 10³ compared to current GW detectors.
This talk will focus on the ongoing activities of the magnetic noise work-package group for ET, including magnetic investigations related to current measurement campaigns targeting anthropogenic sources, simulation studies for mitigation strategies to integrate into the infrastructure, and the prototypes developed.Speaker: Barbara Garaventa -
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Modelling low-frequency control noise for the Einstein Telescope and deriving a requirements matrix
Angular sensing and control (ASC) noise will play a crucial role in designing the low-frequency interferometer of the Einstein Telescope (ET). We have to ensure at an early design stage of the project that we can achieve tolerable levels of ASC noise that won't limit the target sensitivity of ET. ASC noise arises at the interface of the optical and mechanical systems and sets requirements on both the suspension system and the controls of the optics. In the framework of the Low-Frequency Control Noise Work Package we are planning to investigate this interface. We are developing a Finesse model that will incorporate the high-fidelity suspension model provided by the Suspension Division as well as the optical layout of the Dual-Recycled Fabry-Perot Michelson Interferometer provided by the Optics Division. The two have to be integrated into a unified Finesse model to correctly take into account the radiation pressure effects with a given suspension design and optical layout. In particular, with such a model we can probe how the beam spot offset modulates the coupling of the angular sensing noise into the main degree of freedom (DARM). Requirements on the beam spot RMS and sensing noise are interdependent, therefore our first goal is to provide a requirements matrix: for a given set of beam spot RMS values, provide a set of acceptable sensing noise values and vice versa. As a next step we are planning to include the effects of the longitudinal sensing and control noise (LSC) and more realistic constraints on the sensing/actuation matrix.
Speaker: Artem Basalaev -
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Depth- and Distance-Dependent Correlated Seismic Noise Analysis at LSBB and Implications of Newtonian Noise Mitigation for the Einstein Telescope
Correlated seismic noise and the resulting Newtonian noise (NN), pose a significant challenge for future gravitational-wave detectors like the Einstein Telescope (ET), especially for low-frequency gravitational-wave background (GWB) searches.
The body-wave-induced NN could significantly impact ET's sensitivity to GWB by orders of magnitude in its most sensitive frequency band.
This study characterizes correlated seismic noise over varying horizontal separations and depths at the Laboratoire Souterrain à Bas Bruit (LSBB) to assess this impact and inform about NN mitigation strategies as well as potential design choices (e.g. exact depth of the facility).
The seismic data is being collected utilizing three mobile seismometers alongside three fixed LSBB sensors to capture seismic field fluctuations at distances exceeding 250 m.
In this talk, we discuss results from the analysis that focuses on horizontal separations of approximately 275 m, 550 m, and 825 m, while also evaluating depth-dependent effects.
Coherence and cross-spectral density (CSD) analyses reveal strong seismic correlation below ~2 Hz, with significant correlation persisting up to ~40 Hz, particularly at the shortest (~275 m) separation relevant for ET's inter-detector distances.
This finding provides confirmation of the correlated underground seismic noise, which can be used to predict the resulting correlated NN.
These LSBB site specific results quantify the challenge posed by correlated seismic noise for ET's low-frequency GWB searches and provide essential input for developing and validating the effective NN cancellation strategies vital for ET.Speaker: Anoop Koushik (BelGrav UAntwerpen)
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OSB & EIB joint session Rooms 215 & 216
Rooms 215 & 216
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Report from EIB Div1Speaker: Andres Tanasijczuk (Universite catholique de Louvain)
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79
Report from OSB Div10
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Results from MDC1
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EIB Div4 and LL computing modelSpeakers: Paul Laycock, Steven Schramm (University of Geneva)
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Discussion on MM science and the LL computing model
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Site Preparation & Characterization (SCB) Room 409 at INAF-OAS
Room 409 at INAF-OAS
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84
Infrasonic Noise Analysis at Sos Ennatos
A designated area near the Sos Enattos mine (Lula, Nuoro Province, Sardinia, Italy) has been proposed as a candidate site for the Einstein Telescope (ET), a next-generation gravitational wave observatory requiring an exceptionally low-noise environment. To assess infrasound conditions relevant to ET, a set of infrasound microphones was installed at Sos Enattos, both on the surface and underground, in the fall of 2022. Nearly two years of continuous data have been collected, enabling a detailed analysis of infrasound propagation and its correlation with environmental factors such as wind speed, atmospheric pressure, and other meteorological conditions. The study examines the coherence between sensors and evaluates the effectiveness of underground placement in mitigating infrasound noise. Understanding the infrasound environment at Sos Enattos is essential for assessing the broader site’s suitability for ET. This work presents an overview of the monitoring campaign, analysis methods, and preliminary insights into the site's infrasound characteristics.
Speaker: Wathela Alhassan (Nicolaus Copernicus Astronomical Center) -
85
Geological, petrophysical, geotechnical and hydromechanical assessment of the Lusatian Granodiorite for the construction of the Einstein Telescope
The Einstein Telescope (ET) is a proposed next-generation underground gravitational-wave detector in Europe, anticipated to enhance sensitivity by an order of magnitude compared to existing detectors while extending the observation band down to frequencies as low as 2 Hz. A thorough site characterization is critical for ET, considering geological, hydrogeological, and geotechnical conditions. Geological evaluations must address the identification of frequently vaguely known structures like faults and fractures that could compromise tunnel stability and environmental integrity. Hydrogeological assessments focus on rock permeability to design effective drainage systems and mitigate groundwater hazards. Additionally, a comprehensive geotechnical characterization of the underground environment is essential for ensuring safe construction and operational practices.
To facilitate this, the DZA-01/2022 borehole was drilled into the Lusatian granodiorite to a depth of 250 meters, penetrating sedimentary overburden. The borehole and core samples were characterized geologically, geotechnically, hydrogeologically and petrophysically, revealing key insights into rock quality, strength, density, porosity, and permeability. Despite passing through an old seismic fault zone, findings indicate high rock strength and low permeability below the altered paleosurface, suggesting favorable tunneling conditions with minimal water ingress. Overall, this geotechnical assessment demonstrates that the rock mass is suitable for tunnel construction at this depth, supporting the viability of the proposed underground facilities for the Einstein Telescope.Speaker: Peter Achtziger-Zupancic (Fraunhofer IEG) -
86
Integrated Analysis Approach for Territorial Data at the Einstein Telescope Site in Sardinia (Italy)
The Sardinian site, identified for the underground Einstein Telescope (ET) gravitational wave observatory, features a complex morphology with distinctive geological characteristics typical of stable crystalline basements. The area is also marked by deeply incised valleys, underscoring the need for a detailed and comprehensive understanding of the territory to support site assessment and risk mitigation planning. These characteristics not only enhance the suitability of the site for an underground installation but also introduce challenges to investigate its geological structure at depth to better manage the interactions between the surface processes and subsurface structures.
To address these challenges, a detailed three-dimensional terrain model is being developed, which is integrated with a robust geological interpretation of morphological lineaments and a surface deformation analysis derived from satellite radar interferometry (InSAR). By combining high-resolution Digital Terrain Models, updated surveys, Synthetic Aperture Radar (SAR) imagery, and extensive geological information, we have established a comprehensive cartographic and territorial database within the ETIC project framework. This integrated dataset forms the foundation for evaluating territorial risks and supports the extraction of morphometric maps that identify tectonic structures, landslide-prone slopes and hydrographic networks, ultimately analysing the distribution of meteo-climatic parameters and improving the assessment of real hazard conditions in comparison with historical data.
This dataset, integrated in the 3G4ET Geographic Information Systems (GIS) web-based platform, can be implemented with alternative Building Information Modelling (BIM) of the underground facilities and advanced geological modelling, representing a valuable tool for investigating different geolocation scenario and an essential input for seismic noise analysis. The platform is designed to be continuously refined and enriched with site-specific imagery and data emerging from ongoing studies and future survey campaigns, ensuring that the model remains adaptive and up to date.
This comprehensive approach, which merges multidisciplinary data sources and advanced modelling techniques, lays a robust foundation for assessing both the feasibility and the risks associated with the Einstein Telescope underground site in Sardinia. Furthermore, it offers a scalable framework for territorial risk analysis that can be replicated in similar geotechnical and infrastructural projects, promising significant impact on future developments in the field.Speaker: Monica Marzario (Sapienza, University of Rome) -
87
Update on drilling campaigns 2024 and 2025 ET EMR
Between March 2024 and January 2025, 11 boreholes got cored between 250 - 400 m depth. The total cored depth amounted to about 3600 meters. Four boreholes were finalized as a deep seismometer station, the others as deep piëzometer stations. The subsurface team is still analysing the results of the boreholes and existing geophysical data. Some preliminary findings about the geological structures will be shared.
Speaker: Bjorn Vink (Nikhef) -
88
Geological exploration and new configuration selection for the candidate Einstein Telescope site in Sardinia (Italy)
The Einstein Telescope (ET) will be Europe's next-generation underground interferometric gravitational wave detector. The extreme target sensitivity that these detectors should attain requires underground placement to shield the apparatuses from the ambient noise. A quiet environment in a geologically stable area away from major faults and industrial activities also helps to maximise the duty cycle of the machine.
Among the competing European sites, Italy - recently supported by other partner countries - has proposed northeastern Sardinia as a candidate site. The island's current geodynamic stability, exceptionally low seismicity, and minimal anthropogenic seismic noise make it an ideal setting for high-precision experiments. In this contribution, we provide an update on the geological exploration results relevant to the selection of the ET configuration.
Two geometries are under consideration: a new triangular layout with 11 km of sides, and an L-shaped design with arms of 15 km length. Since 2019, extensive studies have been carried out in the area through academic research; a public tender has been launched in 2024 to expand these efforts. These investigations include a dozen drill holes and geophysical surveys over a crystalline basement with rugged topography reaching elevations of up to 1000 meters. Combined with geological mapping and hydrogeological data, these surveys will support the development of a 3D geological model, including subsurface water circulation and hydrogeochemical and isotopic characterization.
In order to assess also the fourth dimension of long-term geological risks such as seismic faulting, magmatic activity and ground movement, this study also includes geochronological, thermochronological and ground motion characterization analyses.Speaker: Dr Giovanni Luca Cardello (Università degli Studi di Sassari)
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84
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Poster Session
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89
3D geological modelling and groundwater simulation for the Low Seismic Lab and Einstein Telescope in Lusatia, Saxony
A new large-scale research center is established in Lusatia, the German Centre for Astrophysics (DZA). One part of this will be the Low Seismic Lab (LSL), which is to be built in the Lusatian granodiorite in the region between the eastern German cities Hoyerswerda, Kamenz and Bautzen. This underground laboratory is a place of seismic tranquility, which is required for the trouble-free operation of sensitive research equipment. The granodiorite complex, which is bordered by graywacke to the west and the Görlitz slate mountains to the east, is also being discussed as a possible location for the planned Einstein telescope (ET).
As part of this project, the Chair of Engineering Geology and Environmental Geotechnics at TU Bergakademie Freiberg is creating a geological-tectonic 3D model of the area in western Lusatia using SKUA-GOCAD software. The model is based on drill logs and geophysical data from the Geological Survey of Saxony. In particular, the distribution of the granodiorite, but also the occurrence of kaolin and the distribution of the Quaternary and Tertiary overburden will be visualized. In addition, main faults and the adjacent geological units will be modeled.
The model will be used to identify additional drilling locations to locally extend the existing information and thus contribute to a more precise overall picture. It will provide the geometric basis for modeling noise effects and for adjusting the location of the Einstein Telescope (ET) in the granodiorite complex.
In a next step the geological model will be transferred to a finite element groundwater model, taking into account existing hydraulic and hydrological data, new permeability measurements on drill cores and possibly hydraulic borehole tests. The hydraulic model will be used to evaluate the impact of the groundwater on the planned underground laboratory and to design an optimized drainage system. This should minimize the use of pumps in order to avoid seismic noise.Speaker: Sandro Körschner (TU Bergakademie Freiberg) -
90
A Combined Approach Using Empirical Mode Decomposition and Maximal Information Coefficient for Gravitational Wave Detector's Characterization and Noise Hunting
The sensitivity of gravitational wave detectors, such as those used in the Laser Interferometer Gravitational-Wave Observatory (LIGO), is significantly affected by various noise sources, many of which are nonlinear and non-stationary. To effectively characterize and mitigate these noise artifacts, we propose a novel methodology that combines Empirical Mode Decomposition (EMD) and the Maximal Information Coefficient (MIC). EMD adaptively decomposes complex signals into intrinsic mode functions, allowing for a detailed analysis of transient and frequency-varying noise. MIC, on the other hand, quantifies statistical dependencies between different detector channels, enabling the identification of correlated noise sources. By integrating these techniques, our approach provides a robust framework for noise hunting, improving the accuracy of detector characterization. We demonstrate the effectiveness of this method through applications to LIGO data, showcasing its potential to enhance gravitational wave searches by refining noise identification and mitigation strategies.
Speaker: John Oh -
91
Development work for the first ideas towards a fast UHV shutter system for the Einstein-Telescope.
The Research Center Jülich is part of a collaboration with the RWTH Aachen in developing dedicated items of the UHV system for the ET. One importing item is the protection of the detectors at the three key points of the triangular system. Therefore, a fast-closing shutter system should be developed. The investigations will comprise both numerical simulations, development of a technical system as well as building up a mock up and various tests.
In this paper the actual work for the Einstein Telescope will be presented as well as future plans.Speaker: Mohamed Elbashbishy -
92
Exploring the feasibility of neural likelihood estimators to speed up gravitational waves inference for 3rd generaton gravitational waves detectors
Gravitational-wave (GW) astronomy has become routine with almost 200 GW detections in the ongoing observing run of the current network of ground-based detectors. With the next generation of GW detectors with higher sensitivities being planned, the volume and the complexity of the detected signals are expected to rise dramatically, increasing the computational cost and resources of running Bayesian analysis to unsustainable levels. Many alternatives to classic stochastic sampling algorithms have recently been proposed, particularly implementing machine learning components in the Bayesian frameworks. In this work we explore the capabilities and the limits of neural likelihood estimators (NLE) in the context of GW analysis, comparing computational costs and accuracy with standard samplers. We apply our method to simulations as well as real GW signals and show that we are capable of reproducing the posterior probablity distribution functions of parameters with a reduction in computational costs by a factor of ~50. Although our proposed method has its limitations, we show that NLEs show promise as a cheap and flexible framework for GW data analysis.
Speaker: Luca Negri -
93
Gravity Gradient Noise Mitigation using Deep Learning
The Einstein Telescope aims to improve sensitivity by at least an order of magnitude compared to current detectors. The dominant noise source in the region of 1 to 10 Hz is expected to be Newtonian Noise (NN) from seismic activity in the surrounding rock. In order to reach the desired sensitivity, NN must be actively mitigated. Seismometers will be installed in boreholes around the mirrors to measure the seismic activity. The current standard method to predict the mirror response from seismometer measurements is the application of linear filters. We propose a neural network architecture to estimate the mirror response from seismometer readings. We find, that this approach delivers improved results.
Speaker: Jan Kelleter (RWTH Aachen University) -
94
Mitigating the Impact of Wind Turbines on the Einstein Telescope
Characterizing the seismic impact of nearby wind turbines is crucial for future gravitational wave detectors like the Einstein Telescope.
Their vibrations pose a challenge to gravitational wave detection especially in the low frequency range where direct and gravitational couplings are the limiting factors.
This poster will explore and discuss the influence of different wind turbine tower constructions on the frequencies of the vibrational eigenmodes.
Seismic measurements and finite element method (FEM) simulations will be used to characterize the oscillation behavior of a wooden tower wind turbine and compare it to a conventional steel tower.
Further FEM simulations will give an insight into additional construction options, such as lattice/girder masts, steel towers of different heights and hybrid towers.Speakers: Niklas Nippe, Tom Niggemann -
95
Octopyus: A Frequency-Domain Simulation Tool for Superattenuator Suspensions
The next generation of ground-based gravitational wave detectors will push the boundaries of our understanding of the Universe. The Einstein Telescope aims to surpass current observatories by achieving unprecedented sensitivity, particularly at low frequencies. This improvement relies on advanced seismic attenuation systems, crucial for reducing environmental noise and enhancing detection capabilities.
In this talk, we present Octopyus, a software developed for the mechanical simulation of a superattenuator suspension. The tool is based on the impedance matrix method, enabling system modeling in the frequency domain. Designed for accessibility, Octopyus automates the computational process, allowing users to perform simulations without requiring in-depth knowledge of the underlying mathematical framework. The software includes standard passive components found in superattenuators and is structured to incorporate active control systems.
We will showcase simulated frequency responses and compare them with results from other simulation tools. Additionally, we will analyze thermal noise behavior under different conditions, demonstrating the software’s potential in refining suspension system design for next-generation gravitational wave detectors.
Speaker: Matteo Montani -
96
Optimizing Hartmann Wavefront Sensor performances for direct measurement of optical aberrations.
Increasing the sensitivity of gravitational wave detectors is a highly complex challenge which requires their stable operation at progressively higher power levels. Optical power absorption in the Fabry-Perot cavities leads to thermally induced aberrations that, if not compensated, degrade the interferometer's performance. Therefore, the measurement and correction of these optical aberrations stand as one of the key technological challenges for the operation of gravitational wave interferometers. The Virgo-ET research group at the University of Rome "Tor Vergata" is actively involved in the development of the Thermal Compensation System (TCS), designed to measure and mitigate optical aberrations, to meet the highly demanding requirements of future detectors such as Einstein Telescope.
Currently, in Advanced Virgo, direct wavefront monitoring is performed by the Hartmann Wavefront Sensor (HWS), a differential measurement device developed in collaboration with the LIGO group at the University of Adelaide (AU). To meet the demands of next-generation detectors, a new HWS has been designed featuring a CMOS sensor. Testing has confirmed that the new system achieves a wavefront reconstruction accuracy ≤ 0.4 nm RMS.
This presentation will describe the Hartmann Wavefront Sensor ongoing improvements in preparation for its use in third-generation detectors.Speaker: Matteo Ianni (INFN, Section of Rome Tor Vergata, Rome, Italy. University of Rome Tor Vergata, Department of Physics, Rome, Italy) -
97
Preparing for thermal aberrations mitigation in ET: Wavefront Sensing and Control developments at AiLoV-ET
Future high-power operation of Einstein Telescope (ET) in its high-frequency dedicated incarnation (ET-HF), is expected to amplify the impact of thermally-induced optical aberrations, posing new challenges for beam quality and interferometric stability. Building on the legacy of thermal compensation systems developed for Advanced Virgo, we are currently investigating advanced wavefront sensing and control (WS&C) concepts aimed at addressing the needs of next-generation detectors within the AiLoV-ET (Advanced Optics Lab @ Tor Vergata for ET) infrastructure.
A dedicated testbench is being developed to serve as a central platform for investigating thermal aberrations and validating wavefront control strategies under realistic interferometric conditions. Around this core setup, several R&D activities are underway — including improved laser beam shaping, adaptive thermal actuation, and enhanced wavefront sensing — to support both the investigation of fundamental limitations and the development of novel compensation strategies.
This contribution will provide an overview of the WS&C activities currently underway within AiLoV-ET, highlighting the experimental platforms and technologies under development to support the ambitious goals of ET-HF.
Speaker: Diana Lumaca (INFN Sezione di Roma Tor Vergata) -
98
Re-solving multi-messenger puzzles with Very Long Baseline Interferometry
The detection of information carried by means other than electromagnetic waves has opened a new era in the study of the Universe. Very Long Baseline Interferometry, thanks to its exquisite angular resolution, remains the only technique allowing astronomers to directly image the most compact structures associated with the emission of energetic photons or other carriers of information, as well as their evolution. An outstanding example was the observation of the formation of a jet following the first - and so far unique - concurrent detection of gravitational and electromagnetic waves in GW 170817. I will present the observational and astrophysical novelty of the VLBI campaign following this event, and the prospects for future synergies between VLBI and next generation GW detectors, especially focussing on the Einstein Telescope.
Speaker: Marcello Giroletti (INAF Istituto di Radioastronomia, Bologna (Italy)) -
99
The ETICo2 Laboratories, a state-of-the-art facility for opto-electronics and coatings for ET
The ET Infrastructure for Optics and Electronics in Cagliari (ETICO2) is a part of the ETIC project aiming at establishing a set of state-of the art laboratories dedicated to optoelectronics and coatings for ET. The facility has been recently established at the Department of Physics of the University of Cagliari as result of a collaboration between INFN and Cagliari University.
The new R&D facilities include a state-of-the-art clean room equipped with advanced systems for testing and assembling optoelectronic devices. They also feature a cutting-edge thin-film fabrication laboratory with a thermal evaporator and e-beam deposition technology for mirror coatings. In addition to a state-of-art setup for thermal and magnetic properties characterizations, a newly developed optical diagnostic laboratory and a thermo-magneto-optic laboratory, along with a high-performance computational facility, are currently being outfitted to further enhance research activities.
This infrastructure will support the development of enabling technologies of the ET interferometers such as advanced photonic and electronic devices for monitoring the next-generation gravitational wave detector and the manufacturing and testing of dielectric materials and multi-layer coatings for the mirrors of the Einstein Telescope.
A comprehensive overview of the ETICo2 laboratories will be presented at the symposium, highlighting their current status and their future role for the Einstein Telescope in Sardinia.Speaker: Andrea Lampis -
100
Towards a FAIR path for the Einstein Telescope
The third generation Gravitational Wave detectors such as the Einstein Telescope, and the future instruments for astronomy and astrophysics to be released in the next years will generate an increased amount of data of considerable complexity, that will be available to the astrophysics community. This poses important challenges in order to store, process, integrate, distribute, share and analyze these vast amounts of data in a way that is safe, organized and efficient. The FAIR principles — Findable, Accessible, Interoperable, and Reusable — are therefore crucial for Gravitational Wave science by enhancing good data and software management practices.
In the context of Working Package 8 (Computing and Data Access) from the Einstein Telescope Preparatory Phase project (ET-PP), we present our vision of a potential strategy for data and software management for the Einstein Telescope based on the FAIR principles. By leveraging on published resources, we explore how a future FAIR path for ET could be implemented, also identifying topics in which further work is required. Establishment of a solid and curated FAIR path for Gravitational Wave science will ensure that current and future researchers from the field can easily identify, locate, access and reuse open materials and resources for successful implementation of the FAIR principles along the scientific data and software life cycles, providing them with the robust framework necessary for advancing this transformative area of astrophysics.
Speakers: Oscar Reina (Barcelona Supercomputing Center), Nadia Tonello (Barcelona Supercomputing Center) -
101
Update on modelling activities and bond strength trials from Glasgow
We present updates on the modelling work happening in Glasgow towards the design of prototypes for the next generation of suspensions. The previous models of advanced LIGO are reviewed, and the effect of deviations from ideal scenarii on the suspension thermal noise are studied. As we make progress towards the definition of parameters for our cryogenic suspension, bond strength trials and safety factors are discussed. We also address modelling suspension dynamics, and scaling up towards heavier masses such as the ones in ET.
Speaker: Gregoire Lacaille (University of Glasgow) -
102
Update on the feasibility analysis of a cryogenic test-mass suspension with flexures operating in compression
This presentation provides an update on the feasibility analysis of a novel suspension for the cryogenic test-mass mirrors of the low-frequency detector of the Einstein Telescope. To overcome the severe limitation imposed on traditional suspensions by the tensile stress for simultaneously achieving low thermal noise, safer mechanical margins and high thermal conductance, this configuration takes advantage of the many times higher compressive strength of silicon with respect to its tensile strength. We propose the use of vertical rigid beams with large cross sections working in tension, combined with short flexures working in compression. The flexures are mechanically robust and at the same time soft in the working direction, thus producing low suspension thermal noise and, by being short, they provide high thermal conductance for cryogenic cooling. The beams have negligible vertical elastic compliance, but they are still subject to unavoidable machining tolerances, so vertical blade springs must be used to provide elastic compliance.
After briefly reviewing some basic results about the mechanical and thermal behaviour, the presentation will focus first on the feasibility of using optical anti-springs to reduce the pendulum resonant frequency to further improve the vibration isolation of the test mass. Then, the suspension thermal noise calculated with a rigid-body model will be presented. Finally, an introduction will be given on the possibility of using active anti-springs to reduce the resonant frequency of the blade springs to achieve useful vertical vibration isolation.Speaker: Fabián Peña Arellano -
103
Advanced Coating Studies for the Einstein Telescope: Optical, Mechanical, and Topo-Morphological Characterization at AiLoV_ET Laboratory in Rome Tor Vergata
The next-generation gravitational wave observatory, Einstein Telescope, requires coatings with extremely low losses to enhance its sensitivity. Our research focuses on the development and characterization of oxide and nitride coatings deposited using sputtering techniques. We investigate how impurities and stoichiometry influence their properties.
To this end, we have established new laboratories dedicated to optical and mechanical characterizations, including a clean room equipped with a Photothermal Common Path Interferometer for highly precise absorption measurements at 1064 nm and 1550 nm. Furthermore, a dedicated cryostat equipped with a Gifford-McMahon cryocooler and a Gentle Nodal Suspension for dissipation measurements has been designed and produced.
Additionally, we leverage a research facility that provides a scanning electron microscope for morphology analysis, an atomic force microscope for topography, and energy-dispersive X-ray spectroscopy for stoichiometric evaluation—all integrated within the same system. Complementary analyses are performed using X-ray photoelectron spectroscopy to investigate surface chemistry and Raman spectroscopy to assess molecular and structural properties.
These comprehensive studies aim to optimize coating performance for future ET applications.
Speaker: Valerio Scacco (Dipartimento di Fisica, Università degli Studi di Roma Tor Vergata; INFN sez. Roma Tor Vergata) -
104
AEI 10m Prototype - Recent developments towards the Sub-SQL Interferometer
As gravitational wave detectors continue to advance, enhancing their sensitivity remains a crucial challenge. Performance is limited by various noise sources, including seismic, thermal, and quantum noise. Developing techniques to mitigate these limitations is essential for the development of the Einstein Telescope interferometers.
The AEI 10m Prototype is a prototyping facility closely resembling a gravitational wave detector. The facility serves as a unique testbed for new advanced technologies as it will operate a Fabry-Perot Michelson interferometer designed to be nominally limited by the Standard Quantum Limit (SQL) where quantum radiation pressure noise and shot noise intersect. Additionally, the ultra-low noise environment makes it ideal for testing other technologies such as inertial sensors and control techniques.
An update on the progress and recent developments will be presented. Some of the topics discussed will include current progress towards setting up the so-called Sub-SQL Interferometer, the improvement of the input beam with an additional Input Mode Cleaner and the preparation of the quasi-monolithic suspensions.Speaker: Ms Sara Al-Kershi (Max-Planck Institute for Gravitational Physics) -
105
Blind source separation in 3rd generation gravitational-wave detectors
The Einstein Telescope (ET) and Cosmic Explorer (CE), as next-generation gravitational-wave (GW) observatories, will achieve unprecedented sensitivity, detecting an immense number of GW signals across an extended frequency range. This improvement introduces a fundamental challenge: the presence of overlapping GW events in both time and frequency, complicating signal extraction and parameter estimation. Existing search pipelines assume isolated signals, but with BBH detection rates expected to reach 10^5–10^6 events per year, advanced signal processing techniques will be required to disentangle these overlaps effectively.
This work explores the application of Blind Source Separation (BSS) techniques—such as Independent Component Analysis (ICA), Non-Negative Matrix Factorization (NMF), and machine learning approaches—to gravitational-wave data. BSS methods, widely used in telecommunications and biomedical signal processing, offer a promising avenue for separating multiple overlapping sources without prior knowledge of their individual waveforms. We assess the feasibility of integrating these methods into next-generation GW data pipelines, considering constraints such as detector noise, real-time computational demands, and the evolving spectral characteristics of GW signals.
By adapting and optimizing BSS methods for the specific challenges of ET and CE we could enhance parameter estimation accuracy, mitigate biases in source characterization, and improve multi-messenger follow-up strategies. This study highlights the need for hybrid approaches combining BSS with traditional GW search algorithms to fully exploit the scientific potential of future GW observatories.Speaker: Francesca Badaracco (Unige) -
106
CALVA, a facility for frequency dependent squeezing
CALVA is an experimental facility at IJCLab (Orsay, France), hosting a 50-m long suspended optical cavity. It is mainly dedicated to quantum noise reduction experiments with the development of an in-vacuum squeezing source and a linear three-mirror cavity as squeezing filter cavity. In this poster I will present the infrastructure, the on-going experiments and the projects foreseen for gravitational wave detectors (Advanced Virgo and Einstein Telescope).
Speaker: Angélique Lartaux (IJCLab) -
107
Continuous gravitational waves: Mock Data Challenge and detectability in ET
We investigate the detectability of continuous gravitational waves (CW) - weak, long-duration signals emitted by asymmetric, rotating neutron stars (NS). Despite current gravitational wave detectors not yet providing a confident detection, future instruments, notably the Einstein Telescope (ET), could move CW signals from theory to observation. Our analysis estimates the number of isolated sources that would produce detectable signals based on their signal-to-noise ratio (SNR) over specified observation time and across a range of possible ellipticities, which measure the degree of pulsar's deformation. The numerical model used in our study is built on a pulsar population synthesis within the gravitational potential of our galaxy and will be implemented as part of the ET’s Mock Data Challenge (MDC).
Speaker: Hanna Strozyk (University of Warsaw) -
108
Cosmology with GWxHI Cross-Correlation with Future Observatories
We explore the potential of cross-correlation between gravitational waves (GWs) and 21 cm intensity mapping (IM) from neutral hydrogen emission (HI), focusing on its role in view of future high-precision observatories, specifically Einstein Telescope (ET) and the Square Kilometer Array Observatory (SKAO). We model the large scale structure evolution by making use of 3D lightcones of the dark matter density distribution up to redshift $z \sim 3$ from both linear perturbation theory and N-body simulations. Assuming that GW and HI are different tracers of the same underlying density field, we infer cosmological parameters from both the angular power spectrum (auto-correlation) and the angular cross-power spectrum (cross-correlation) of these probes. We show that synergies between future GW and HI experiments will significantly improve standard sirens measurements, thanks to increased sensitivity and high-redshift coverage, allowing to constrain cosmological parameters to a level comparable to that of well-established alternative probes, such as Type Ia Supernovae.
Speaker: Matteo Schulz (Gran Sasso Science Institute) -
109
Detectability and parameter estimation capabilities of different configuration designs for Einstein Telescope (using GWJulia)
Future detectors of gravitational waves will be able to detect tens of thousands of compact binary coalescences every year. It is then important to have a quick and reliable way of performing the parameter estimation of these sources and the most common tool used in the literature for this purpose is the Fisher matrix. During this talk, I will present the open source code GWJulia, which performs Fisher matrix analysis of parameters of compact binary coalescences.
The code is written in Julia, making it significantly faster than the other codes available in the literature while maintaining the same level of accuracy.
Later, I will also present a case study using this code, comparing different designs for Einstein Telescope. I will present a comparison between a 10km triangular interferometer and two 15km L shaped interferometers with different orientations. In particular, I will focus on the detection of golden events and cosmological applications. Moreover, I will highlight a possible route of using the Fisher matrix to improve the convergence of MCMC sampling of future events.Speaker: Andrea Begnoni -
110
ET-OPT - A facility for optical mode control at high intracavity powers
LIGO and Virgo are limited in the amount of power they can build up in the arms. The limitation arises from the absorption of optical power in the main optics, causing mirror surface deformations. This in turns couples scatters light into higher order modes and causes several problems, notably, parametric instabilities, degraded buildup of the control sidebands and limited squeezing enhancement. ET-HF plans to use 3MW of optical power, in contrast, during O4 LIGO planned to use 750 kW and achieved 350 kW.
In this presentation, I describe plans for the ET-OPT facility, a high optical power facility in the EMR region. We will construct a suspended optical cavity, operating at similar peak intensity and g-factor to ET-HF. We will use our real-time cavity spectroscopy technique to measure mirror surface deformations as the cavity thermalises and demonstrate that the optical mode basis can be brought back under control. In this talk, we introduce the real-time cavity spectroscopy technique and then describe the plans for the facility.
Speaker: Aaron Goodwin-Jones (UCLouvain) -
111
Impact of the Einstein Telescope in Sardinia (Italy): Well-Being & Sustainability Indicators
One of the key requirements for achieving the expected sensitivity in detecting weak gravitational waves is to secure an area free from both natural and anthropogenic noise. For this reason, the proposed Italian site for the Einstein Telescope is located adjacent to the former Sos Enattos metalliferous mine in northeastern Sardinia (Province of Nuoro). Sardinia’s unique tectonic setting—as a microplate separated from the Eurasian Plate—ensures exceptional seismic stability, characterized by extremely low local seismicity and a lack of active tectonic phenomena, along with ideal rock formations for underground facilities. Moreover, the rural area benefits from minimal human and industrial activity due to its low population density.
To evaluate the potential impact of the future gravitational wave detector, an in-depth territorial analysis of Sardinia was conducted. This study examined statistical indicators and territorial data to assess accessibility, economic well-being, productive structures, and environmental and landscape characteristics. The analysis was carried out at both regional and municipal levels—with particular focus on the municipalities involved in the detector’s configuration—to provide a detailed overview of the local context, highlighting strengths and identifying potential challenges.
Economic and social well-being indicators were used to assess local quality of life and socio-economic conditions, complemented by an examination of demographic and economic dynamics—particularly development trends and population distribution. This was further enriched by evaluating local infrastructure and the availability of essential services, offering a comprehensive view of the region. Additionally, environmental and landscape contexts were explored to highlight the area’s natural attributes and conservation status, while potential environmental risks such as pollution and extreme weather events were scrutinized. Finally, the criteria for environmental sustainability were considered, emphasizing the Einstein Telescope’s potential to integrate harmoniously with its surroundings by minimizing negative impacts and promoting eco-friendly solutions.Speaker: Mrs Paola Reggio (CRESME Ricerche) -
112
Magnetic noise mitigation for Einstein Telescope: optimization of ferromagnetic shielding
At low frequencies (1-100 Hz), the dominant noise sources for the Einstein Telescope (ET) will be of seismic and magnetic origin. In particular, magnetic noise can be categorized into natural noise, primarily caused by Schumann resonances, and self-inflicted noise, generated by the interferometer’s own electronics.
Based on experience from Virgo, achieving the target sensitivity will require reducing natural magnetic noise by at least a factor of three and self-inflicted noise by at least a factor of 100 [1]. Natural noise can only be mitigated by shielding the interferometer’s sensitive components. In contrast, reducing self-inflicted noise requires a dual approach: shielding the sensitive components, as with natural noise, and directly mitigating noise sources by shielding them at the origin.
This poster provides an overview of key magnetic noise mitigation techniques, with a particular focus on the use of ferromagnetic materials for shielding. The poster highlights the benefits and limitations of this approach, emphasizing the need for an optimized and strategic placement of ferromagnetic shielding to maximize effectiveness.
Reference:
[1] Amann, F. et al. Site-selection criteria for the Einstein Telescope. Review of Scientific Instrument. https://doi.org/10.1063/5.0018414Speaker: Dr Federico Armato (UNIGE - INFN Genova) -
113
Minimum-length metric: A tool to describe possible quantum features of horizons
Many pieces of evidence point to existence,
at least at en effective level,
of a lower limiting length of quantum origin.
A mathematical tool is here presented which accomplishes the task
of endowing spacetime with a description of distances
with a minimum length incorporated, meaning that distances between
any two space or time separated points tend to a finite limit
when the points go to coincide.
We show how this construction can be meant to include also
the case of null separated points (in spite of being distances
identically vanishing for them).
The latter possibility turns
out to be relevant for describing the evolution
of (quantum) horizons, as their generators are null;
in particular it predicts
that their area can change only by finite (and calculable) amounts.
We speculate on the possibility to see this quantum effects
in the gravitational wave signal from the inspiral phase
of binary black hole coalescences.Speaker: Alessandro Pesci (INFN Bologna) -
114
Revisiting Predictions for Eccentric Blak Hole Merger Rates
Black hole binary mergers in dense stellar environments (such as globular clusters or galactic nuclei) are expected to retain non-negligible orbital eccentricity up to the point of gravitational-wave emission. Detecting residual eccentricity at merger would provide a clear signature of dynamical formation channels. Previous studies have suggested that a few percent of stellar-born binary black hole (BBH) mergers could enter the LIGO/Virgo band with measurable eccentricity, making this an important observable for formation scenarios. However, these predictions often rely on simplified assumptions and eccentricity definitions. Here, we present a systematic investigation using post-Newtonian N-body simulations (including terms up to 3.5PN) of BBH encounters in dense clusters. This approach allows us to accurately model gravitational radiation reaction and relativistic dynamics during close encounters, leading to binary captures and inspirals. We adopt a consistent post-Newtonian definition of orbital eccentricity, measuring it at specified gravitational-wave reference frequencies (such as the dominant f22 mode frequency and the peak GW frequency) to robustly characterize residual eccentricity at merger.
Using this numerical framework, we re-evaluate the fraction of eccentric GW merger events that would be detectable by current (LVK) and future (ET) observatories. Our preliminary results indicate that previously reported high eccentric merger rates were likely overestimated. We find that a substantial subset of events initially classified as eccentric mergers are in fact direct plunge events – single-pass gravitational wave captures that merge on the first close encounter – rather than long-lived eccentric inspirals. When these prompt mergers are accounted for separately, the remaining population of true eccentric inspirals entering the detector band is significantly smaller. This distinction is crucial: direct plunges produce burst-like waveforms with little inspiral phase, whereas eccentric inspirals exhibit extended chirps with orbital modulations. Consequently, the occurrence of detectably eccentric inspiral signals is lower than earlier predictions.Speaker: Alessandro Alberto Trani -
115
The ET Collaboration Code of Conduct
The Code of Conduct defines the expected behaviour within the ET Collaboration and serves as the foundation for maintaining a professional, ethical, and respectful research environment.
As an international collaboration that brings together diverse cultural backgrounds and work styles, ET values inclusivity and cooperation. Scientific achievements are meaningful not only for their impact but also for how they are attained. To uphold these principles, the Member Conduct and Ethics Committee (EMCC) has been entrusted with defining a code of conduct that guides interactions and reinforces mutual respect within the Collaboration.
The ET Boards unanimously endorse the following core values: integrity, fairness, inclusivity and transparency. These values shape professional conduct and interpersonal behaviour, fostering an environment where every contribution is valued. Members are expected to act with honesty and respect, creating a welcoming atmosphere that encourages participation and innovation for the benefit of the entire Collaboration.
Core Principles
• Integrity: commitment to ethical conduct, intellectual honesty and personal accountability.
• Fairness: dedication to impartiality and equitable treatment in all aspects.
• Inclusivity: valuing and leveraging diverse perspectives.
• Transparency: emphasis on open communication and clear decision-making processes.
Unacceptable Behaviour
• Harassment: any unwanted or repeated behaviour or communication that creates an environment which is hostile, intimidating, or offensive.
• Discrimination: unjust or prejudicial treatment of individuals or groups based on personal characteristics such as race, ethnicity, gender or other attributes.
• Intimidation: any actions or behaviours intended to instil fear, coerce, or unduly influence others.
• Use of hate speech: any form of communication—spoken, written, or symbolic—that expresses hatred, incites violence, or promotes discrimination against individuals or groups.Speaker: Monica Marzario (Sapienza, University of Rome) -
116
Understanding gradients of Deep Learning based parameter estimations of binary black hole signals
To estimate the source parameters of a gravitational wave signal from measured strain data, two primary methods are used: Bayesian Inference and Deep Learning. Bayesian Inference provides reliable results but demands significantly more computational resources compared to Deep Learning methods. Thanks to their efficiency, normalizing flows have gained popularity in recent years and are expected to play a key role in data analysis for the Einstein Telescope.
However, the "black box" nature of Deep Learning makes it challenging to interpret the estimations. To gain insight into what influences the estimations, we analyze the gradients within the neural network and visualize them.Speaker: Tobias Reike -
117
A preliminary study of the CAOS seismic background
This study aims to characterize the seismic noise at the CAOS construction site to support the development and testing of suspension systems for gravitational wave interferometers, such as the Einstein Telescope.
Speaker: Alessandro Parisi (Università di Perugia) -
118
Concept Study of a Storage Ring Gravitational Wave Observatory for Earth-Based Multiband Detection and Terrestrial Gravity Noise Mitigation
This contribution addresses a first feasibility study for the measurement of millihertz Gravitational waves (mHz GWs) with a storage ring-based detector design that might aid in noise mitigation for Einstein Telescope (ET) by providing a terrestrial gravity noise (TGN) signal and could potentially enable multiband GW observations from Earth.
We propose an experiment based on the measurement of the time-of-flight signal of an ion chain circulating in a storage ring (circular particle accelerators where ion beams are stored for long periods, emitting synchrotron radiation). Compared to a particle traveling in such a storage ring with unaltered velocity, a GW induces a de- or acceleration, which leads to the built-up of an additional time-delay that particles require to complete a full revolution of the ring. Consequently, a GW signature should be observable as a variation of the relative ticking of such a storage ring clock compared to e.g. a reference atomic clock, which would not exhibit the same variation in its ticking. Due to the long storage duration of the circulating ions, the GW signal encoded in their arrival time is especially sensitive to slowly varying mHz GWs. One of the dominant noise sources inherent to the measurement principle, is the shot noise of the emitted synchrotron radiation of the ions. We derive the synchrotron radiation noise amplitude imprinted in arrival time signals of a circulating heavy ion chain using analytical computations and particle tracking simulations.
A storage ring-based gravitational wave observatory (SRGO) based on such an operational principle is expected to exhibit an optimum design sensitivity in the range of ${10^{-4}\;\text{Hz}}$ up to ${10^{-2}\;\text{Hz}}$, which would open up the possibility for multiband GW observations on Earth. However, as all ground-based detectors, SRGOs face the same challenge of the strong terrestrial gravity noise (TGN) in the sub-Hertz band. This will be a limiting factor for the ability of the next-generation low-frequency GW detectors to detect in this band.
While it is still an open question if a sufficiently high sensitivity for the detection of GWs can be reached by improving the experiment design of SRGOs, it should feasible to capture a TGN signal in the range of millihertz up to Hertz frequencies with with a less accurate apparatus. Therefore, in the future, SRGOs might serve as a TGN sensor, which would help ET and other GW detectors to mitigate TGN and be able to detect lower frequency GWs from Earth.
Speaker: Dr Thorben Schmirander (University of Hamburg, Institute of Experimental Physics) -
119
Conceptual design of a low noise lab-scale He-II supply unit for Q-factor measurements of cryogenic suspensions in GRAVITHELIUM
The ERC project GRAVITHELIUM investigates full-scale cryogenic mirror suspensions for ET-LF, including a novel concept using static superfluid helium (He-II) inside a titanium marionette suspension tube. To investigate the possible dissipative contribution of the superfluid to the quality factor of the suspension, a low-noise lab-scale He-II supply unit, capable of delivering 400 mW of cooling capacity at 1.8 K through a 5 m long transfer line, is required. The conceptual design featuring novel heat exchangers promises significant system performance improvements to state-of-the-art He-II bath cryostats. The transient cool-down process, initiated with supercritical helium flow and completed via pumping on a helium bath, allows for fast cool-down cycles in less than one day, depending on the experimental set-up in the cryostat.
Speaker: Timo Weckerle -
120
Cryogenic Vibration Isolation, reducing low-frequency vibrations for the Einstein Telescope
Current state-of-the-art gravitational wave observatories around the world, LIGO, Virgo, and KAGRA, have enabled the detection of $90$ gravitational waves, with an additional $200$ events in the ongoing O4 observing run [ref]. This is achieved through strain sensitivities in the order from $10^{-18} 1/\sqrt{Hz}$ to $10^{-23} 1/\sqrt{Hz}$ [ref,ref], where current noise requirements of test mass motion at 10 Hz are $10^{-19} m/\sqrt{Hz}$ [ref]. Next-generation detectors, such as the Einstein Telescope [ref,ref], are envisioned to achieve amplitude-spectral-density strain sensitivities on the order of $10^{-24} m/\sqrt{Hz}$ with a broader frequency range [ref,ref], allowing us to address a huge number of key issues related to astrophysics, fundamental physics, and cosmology [ref]. Especially in the low-frequency band, these sensitivities can only be obtained by reducing thermal noise on the mirror and its suspension [ref]. This means that cryogenic cooling is necessary for the Einstein telescope to acquire the desired sensitivities.
Leiden Institute of Physics hosts several research groups specializing in ultra-low temperature experiments, requiring ultra-low vibration levels. Ongoing experiments in our group have demonstrated $30fm/\sqrt{Hz}$ in a cryogenfree dilution refrigerator at $27 Hz$ [ref]. We aim to push this noise floor in a narrow bandwidth to $10^{-15}m/\sqrt{Hz}$ at frequencies of order $10 Hz$. Here, we show the current experimental setup of the Zeppelin experiment [ref], focusing on the vibration isolation system currently employed. We also share preliminary results, including force noise measurements and mode cooling.
Further research will focus on improving the vibration isolation system by co-developing systems designed for the Einstein telescope. The added complexity arising from extra vibrations due to the cooling system will be discussed. This will also include measurements and analysis of cryogenic acceleration sensors to characterize vibrations at millikelvin temperatures.Speaker: Jurriaan Langendorff -
121
Deep reinforcement learning for Lock acquisition optimization in non linear transient phase
The work explores the application of Deep Reinforcement Learning (DRL) to optimize the locking procedure of high-finesse Fabry-Perot (FP) cavities, critical components in Gravitational Wave (GW) detectors. Improving and speeding up the locking procedure for a correct resonance acquisition of these cavities aim to improve the detector’s duty cycle, enhancing the Science Mode time (Accadia et al. 2011).
The locking process is highly challenging due to several non-linear effects, such as cavity ringing and resonance drifts depending on the cavity configuration. These effects spoil the signals used for resonance recognition. Traditional methods like the Modified Guided Lock technique (Bersanetti et al. 2020) mitigate effects as the cavity ring-down by dynamically reducing the cavity speed before engaging the Pound-Drever-Hall technique (Black 2001). However, they remain limited providing non-optimized control impulses for each cavity state. Previous studies have applied DRL and machine learning to control tasks in the GW context, such as alignment optimization (Sorokin et al. 2021, Mukund et al. 2023) and handling non-linear dynamics in longitudinal lock acquisition (Ma, Vajente 2023). Building on these results, we take a different approach by leveraging the power of DRL agents in adapting to the dynamic and non-linear nature of cavity behavior, determining the optimal action for each state. We developed a simulator in order to model the optical response of a FP cavity, considering only the longitudinal degree of freedom and taking into account some of the non-linear effects. Subsequently, the simulator was used to develop a custom Gymnasium environment (Towers et al. 2024) to let the DRL agent, Deep Deterministic Policy Gradient (DDPG) (Lillicrap et al.2016), interacting with the system and learning. Finally, we address the critical challenge of SimToReal (Zhao et al. 2020) transfer and the reality gap, laying the groundwork for real optical applications and potentially offering a predictive, adaptive approach to enhance FP cavity lock acquisition efficiency and reliability.Speaker: Andrea Svizzeretto (University of Perugia and INFN Perugia) -
122
Evaluating deep neural networks for Newtonian noise subtraction in GW detectors
Newtonian noise (NN), arising from local density fluctuations due to seismic activities will limit the sensitivity of next-generation gravitational wave detectors at low frequencies. This study explores deep learning models as non-linear algorithms to predict and cancel NN.
As a preliminary experiment prior to obtaining Einstein Telescope data, we utilise data from the Virgo detector, which has an array of 24 seismometers and a tiltmeter acting as a proxy for surface-wave induced NN. We train deep learning models, including Long Short-Term Memory (LSTM) networks, Transformers, and Convolutional Neural Networks (CNN). Their performance is compared against conventional Wiener filtering methods, known to be the optimal linear filter. Our preliminary results demonstrate strong potential for deep learning methods in frequency bands of interest, indicating that these techniques will be beneficial for the Einstein Telescope.
Speakers: Sacha Peters (Université de Liège), Soumen Koley (Université de Liège) -
123
Explainable autoencoder for neutron star dense matter parameter estimation
In this talk we will present a physics-informed autoencoder designed to encode the equation of state of neutron stars into an interpretable latent space. The input polytropic EoS is encoded in the mass, radius, and tidal deformability values of a neutron star. Unlike traditional black-box autoencoders, our approach incorporates additional loss functions to enforce explainability in the encoded representations. This method enhances the transparency of machine learning models in physics, providing a robust proof-of-concept tool to study compact stars data. We will present our results, which demonstrate that the proposed autoencoder not only accurately estimates the EoS parameters and central density/pressure but also offers insights into the physical connection between equation of state and observable physical quantities. We will also discuss implications for ET, thanks to which neutron-star physics will be largely enriched by new GW observations.
Speaker: Matteo Scialpi (INFN - University of Ferrara) -
124
GWmaps: Online Calculator and Interactive Viewer for Credible Areas of Gravitational-Wave Sky Localizations
The GWmaps webpage (https://virgo.pg.infn.it/maps/) provides an interactive platform for visualizing gravitational-wave sky localizations from the LIGO, Virgo, and KAGRA Collaborations (LVK). This application adheres to the technical standards recommended by the International Virtual Observatory Alliance (IVOA). In this poster, we present GWmaps, highlighting its advanced graphical visualization features and interoperability with existing astronomical software. Finally, we outline the upcoming challenges in multimessenger astronomy anticipated with the future operations of the Einstein Telescope (ET).
Speaker: Giuseppe Greco -
125
Host galaxies and local properties of a complete sample of short Gamma-Ray Bursts
Short gamma-ray bursts (SGRBs) represent a unique class of cosmic events offering valuable insights into the physics of compact object binary systems. From the combined detection of the gravitational wave (GW) event GW170817 with the corresponding electromagnetic counterparts - the kilonova AT2017gfo and the short GRB170817A - interest in compact object binary merger counterparts has significantly increased, leading to extensive follow-up campaigns by ground-based and space telescopes. The Neil Gehrels Swift Observatory (Swift) fast re-pointing capability and precise X-ray afterglow localization by the Swift X-Ray Telescope (XRT) have enabled to secure a noteworthy amount of quality data to perform population statistical studies and shed light on the formation, evolution, and merger of these systems. For this purpose, a sample of short GRBs - the S-BAT4 - has been set up, collecting properties from 2004 to 2022, by means of precise selection criteria in terms of flux limitation and completeness, in order to ensure minimal observational and redshift-related biases. In the talk, I will present the analysis of the environmental properties of S-BAT4 events, including host galaxy features, offsets, and neutral hydrogen column densities (NH) derived from Swift/XRT spectra. Host galaxy properties and magnitudes have been analysed in comparison to carefully selected samples of field galaxies, as well as typical galaxies of long GRBs (LGRBs), to investigate how the environment plays a role in the GRB progenitor systems. Host galaxies of SGRBs have been found to be consistent with bright, mainly star-forming galaxies, with significant differences from LGRB hosts. Specifically, SGRB hosts display higher masses and gas-phase metallicities, while exhibiting lower star formation rates. Offsets and NH have been computed for a significant fraction of S-BAT4 events and analyzed in relation to both host and afterglow properties to shed light on different formation channels for compact object binary systems.
Speaker: Matteo Ferro (INAF-OAB) -
126
Photoinduced Effects in Mechanical Loss and Elasticity of GaAs for Ultra-Stable Laser Interferometers
Crystalline AlGaAs/GaAs coatings are a promising low-noise material candidate for high-precision optical metrology due to their low mechanical loss. However, recent studies have revealed excess Brownian thermal noise in optical cavities, which appears to be linked to photoinduced effects. Additionally, there are indications that illumination influences the mechanical loss in GaAs, leading to changes in Brownian thermal noise.
To investigate these effects, we studied the mechanical loss characteristics of GaAs at 80 K, 200 K, and 295 K under controlled illumination with wavelengths around the GaAs bandgap. Our results show that low-frequency mechanical resonance modes exhibit decreasing losses with increasing photon energy, whereas higher-frequency modes display the opposite trend. As temperature decreases, the behavior of mechanical loss changes.
Beyond mechanical loss, elasticity is also affected, showing a pronounced wavelength-dependent peak. Relaxation effects occur when switching illumination on and off, with timescales ranging from seconds to minutes. Interestingly, at room temperature, infrared light (1550 nm) influences the resonance frequency to a similar extent as blue light (461 nm), despite GaAs being transparent to infrared light and fully absorbing blue light. However, this trend reverses at lower temperatures.
These findings suggest that photoinduced changes in mechanical loss and elasticity may contribute to variations in birefringence observed in AlGaAs/GaAs coatings and could be relevant for understanding excess thermal noise in mirror coatings. While this study does not fully explain all observed effects in GaAs, it represents a step toward a more comprehensive understanding of photoinduced mechanical changes in the material.
Speaker: Nico Wagner -
127
Seismic ambient noise modeling for Lausitz ET candidate site
Understanding the ambient seismic noise field and its attenuation with depth is an important consideration for the decision to build the Einstein Telescope at a proposed site. Here, we perform 2D and 3D ambient noise simulations for the Lausitz region by solving the seismic wave equation using Spectral Element Method (SEM), a high-fidelity numerical technique capable of handling complex geometries and subsurface heterogeneities. Initial simulations incorporate realistic topography, a two-layer velocity model with strong velocity contrast using velocity information from an active seismic campaign, and by randomly distributed seismic sources mimicking the observed background noise field. We assess their individual and combined influence on the simulated ambient seismic noise fields. Firstly, we use 2.5Hz Ricker wavelets to investigate scattering effects caused by topography on observations at surface or buried. While topography induces slight scattering, the presence of a low-velocity surface layer leads to significant differences in amplitude and waveform shape between surface and subsurface recordings. To further explore the ambient noise field, we calculate a Green’s function library using approximate broadband sources and convolve them with different noise sources based on randomly perturbed phase shift. This modular approach enables flexible testing of source configurations and frequency content in a computationally efficient strategy. Preliminary results highlight the importance of both recording depth and noise source distribution in shaping the ambient noise field. These insights are directly applicable to optimizing station deployment and understanding wave propagation in loose sedimentary structures. Future work will extend this framework to a more realistic reflector interface from borehole mapping and seismic reflection studies, realistic source distributions based on local noise sources (e.g. towns, streets, etc.) and detailed comparisons with observed data (at the surface and depth).
Speaker: Mr Shi Yao (Geophysical Institute, Karlsruhe Institute of Technology, Germany;State Key Laboratory of Deep Petroleum Intelligent Exploration and Development, Institute of Geology and Geophysics, Chinese Academy of Sciences, China;University of Chinese Academy of Sciences, China) -
128
Strain variations in Sardinia induced by Glacio-Isostatic Adjustment and hydrological loads
The aim of this work is obtaining a preliminary estimate of expected crustal deformation in Sardinia due to geodynamical processes acting on local and regional scales in response to the past and present variations of surface loads. Solving the “Sea Level Equation” for a spherically symmetric, self-gravitating visco-elastic Earth, we characterize the ongoing vertical and horizontal movements in the western Mediterranean region, in delayed response to the melting of the Holocene ice sheets. An up-to-date chronology for the ice sheets is used in conjunction with a steady state rheological profile for the Earth’s mantle and lithosphere. The surface response in the western Mediterranean and in Sardinia is also characterized in terms of variations of the rate of change of the strain tensor, which are compared to those obtained in regions located in central Europe, closer to the margins of the former ice sheets. We provide quantitative assessments of the glacial isostatic strain rates and compare them to those caused by other sources of local deformation, as the ongoing variations in the surface loads associated with major artificial reservoirs. The displacements induced by the latter are computed through an elastic rebound modeling approach, with which we also provide an estimate of the vertical and horizontal displacements and corresponding perturbations of the strain tensor.
Speaker: Dr Fernando Linsalata (INGV - Roma) -
129
The PIP, a novel seismic isolation filter for third-generation gravitational wave observatories
The low-frequency frontier is amidst the most important challenges for future gravitational waves detectors. Improved low-frequency sensitivity is crucial for detecting high-mass or high-z systems, improving source localisation, enabling timely alerts for electromagnetic follow-ups, and facilitating the detection of predicted gravitational waves from sources like rotating pulsars. In this contribution, we will present ongoing experimental and simulation efforts to support the Pendulum Inverted Pendulum, a novel filter prototype for mitigating low-frequency seismic noise. Such prototype aims at reducing the height and complexity of current attenuation systems, lowering cost and work needed to build the Einstein Telescope detector.
Speaker: Michele Vacatello (University of Pisa, INFN Pisa) -
130
Towards a more realistic Seismometer Position Optimization for Newtonian Noise Mitigation
At the Einstein Telescope, Newtonian noise is expected to be the dominant noise for low frequencies. Its impact is proposed to be reduced with the help of an array of seismometers that will be placed around the interferometer endpoints. As boreholes for seismometers are expensive, their positions should be optimized. Up to now this was done based on an analytical calculation that makes simplifying assumptions.
We have developed a three-dimensional simulation of seismic waves and their effect on a single test mass. It also simulates the displacement measured by arbitrarily placed seismometers. Given the Newtonian noise at the mirror and the seismometer displacement, their positions are optimized based on the Wiener filter. With this simulation, some of the assumptions of the analytical calculation can be lifted, as we move towards a more realistic optimization of seismometer positions for Newtonian noise cancellation.Speaker: Patrick Schillings (RWTH Aachen University) -
131
Adaptive Optics techniques for compensating wavefront errors in gravitational interferometers.
In gravitational interferometry increasing the measuring laser power is a straightforward way to improve the instrument sensitivity, and it has been one of the main points in the upgrades of the existing detector like VIRGO and in the design of future projects like ET. However, the dissipated portion of the high circulating power in Fabry-Pérot arm cavities is enough to heat up and deform the suspended mirror substrates, introducing wavefront distortions that compromise sensitivity. To mitigate these effects many solutions have been studied, and they all share the concept of using a separate source of power (lamp, laser, resistors) to suitably heat the optics and compensate for the aberrations in the interferometer beam. In the framework of the ETIC-PNRR project, INAF-ADONI is setting up an optical bench dedicated to further expand the concept making use of technology and experience borrowed from the adaptive optics (AO) systems developed by INAF for earth-based astronomical observations. The idea is to modulate the heating laser intensity pattern by introducing a local curvature in the wavefront using a deformable mirror (DM). In respect to actual technologies, this would simplify the generation of a structured and optimized intensity pattern on the compensating plate (CP) surface. That means that non-axis symmetrical aberrations can be managed, in principle allowing to compensate not only for the thermal absorption effects, but for wavefront errors due to optics manufacturing or coating imperfections. The final objective of the experiment is to verify the ability to identify the DM deformation to induce a target pattern of optical path difference (OPD) in a glass test piece (GTP), representing the CP, and stabilize time-dependent variations in closed-loop. In this poster we present the functionality of the test bench and the current status of the experimental activity.`
Speaker: simone Lombardi (INAF Padova) -
132
An upgraded payload for the CAOS suspended Fabry-Pérot cavity
The CAOS research center (Centro per Applicazioni sulle Onde gravitazionali e la Sismologia) is under construction in Perugia to test seismic attenuation systems for ET and Virgo and perform seismological research. Two 13 m tall attenuators are currently being designed and manufactured, based on the Advanced Virgo Superattenuator concept to support a suspended Fabry-Pérot cavity with 100 kg test masses. With these increased height and suspended mass, the CAOS attenuators represent a step forward in upgrading the AdV Superattenuator to ET requirements.
The height of the devices allows for more spaced Filters along the chain, including longer distances between the Last Filter and the Marionette and, possibly, between the Marionette and the Mirror. This makes the Advanced Virgo actuation cage scheme unsuitable and provides an opportunity to decouple the Last Filter from the forces applied to the Marionette below.
Similarly to other contemporary projects, we propose a Payload design implementing a suspended Reaction Mass from which to drive the Marionette and the Mirror. We present here the new Payload and the expected performance.Speaker: Piero Chessa (Università degli studi di Perugia / INFN-Perugia) -
133
Current status and perspectives of CoMET laboratory
The COMET (Coating Materials for Einstein Telescope) laboratory of the University of Padua is growing in Rovigo within the ETIC project. This laboratory will be able to produce samples on demand for the international scientific community, fostering the development of new materials and treatments that can, in the future, be reproduced on a large scale to realize the mirrors of ET and other gravitational interferometers. This facility will be dedicated to the production of GW-quality coating samples and to the study of deposition processes crucial for high-quality mirror fabrication. The laboratory will focus on the R&D of innovative optical films characterized by properties such as extreme transparency and high mechanical quality factor. Among its main objectives is the identification and elimination of the physical causes of the optical absorption of coatings and sources of mechanical dissipation. Both of these parameters are critically influenced by complex factors such as the structural, mechanical, compositional, and surface properties of the materials.
CoMET will be equipped with ad-hoc designed deposition machines: a Dual Ion Beam Sputtering system and an Ion Assisted Magnetron Sputtering system for the deposition under controlled conditions of multi-element coatings. During the design of the deposition machines and the facility in general, we have paid a lot of attention to reaching a high level of control of the deposition processes and to minimizing any impurity sources, which can compromise high-quality optical coatings. The machines will also feature several in-situ characterization tools to study the deposition process and the material characteristics while the process is carried out.
The CoMET laboratory is now under construction and will be operational in 2026. In this talk, we will give an update on its status and illustrate the specific details of the possibilities enabled by this new facility to the GW community.Speaker: Hanna Skliarova (UNIPD) -
134
Deformable mirrors for mitigation of non-axisymmetric optical defects for the future gravitational wave detectors
In the context of gravitational wave detectors, optical aberrations primarily arise from laser absorption in coatings and production process defects in the various optics along the laser path. If uncorrected, these distortions can significantly deviate the detector from its optimal working point, making the interferometer unmanageable and drastically reducing its sensitivity. Therefore, the Thermal Compensation System (TCS), designed to detect and compensate for these optical aberrations, is crucial for ensuring the proper operation of the detector. The TCS primarily exploits the thermo-optic effect to correct wavefront deformations by illuminating on-path optics with a shaped CO2 laser beam. Future generations of gravitational wave detectors, such as ET-HF, are expected to achieve unprecedented levels of intracavity optical power, which will amplify the effects of optical aberrations, including non-axisymmetric ones. We are currently investigating Deformable Mirrors (DMs) as a versatile solution to mitigate these non-axisymmetric optical defects. Indeed, DMs can adapt the reflective surface to match a selected phase pattern and reproduce a desired intensity profile. Additionally, DMs do not introduce frequency-dependent noises in the detector’s band due to the static nature of the correction. We employed a Modified Gerchberg-Saxton (MoG-S) algorithm to determine the phase corrections required for intensity compensation on the image plane. This study includes the characterization of a DM equipped with 192 magnetic actuators and investigates phase correction approaches based on the MoG-S algorithm.
Speaker: Luciano Antonio Corubolo (Università degli studi di Roma Tor Vergata; INFN Roma Tor Vergata) -
135
Design update of the ET-LF Superattenuator reference solution
The Superattenuator is a cornerstone in seismic isolation systems for ground-based interferometers and is indicated as the reference solution for the isolation of the test masses of the Low-Frequency Einstein Telescope.
However, the need for an update of the Superattenuator arises not as much from the increased sensitivity requirements, as from the need to suspend a heavier, cryogenic payload, which makes the mechanics more demanding and imposes constraints on the materials, that must be compatible with both vacuum and cryogenic conditions. As seismic isolation system design progresses, evaluating the impact of targeted interventions on the performance of existing solutions is essential.
The upgrade detailed here allows the Superattenuator to meet the more demanding requirements of a third-generation interferometer while preserving its well-established reliability and performance.Speakers: Francesca Spada, Dr Giovanni Losurdo (INFN Pisa), Dr Leonardo Lucchesi (INFN Pisa), Lucia Trozzo (INFN, sez. Napoli), Manuel Pinto, Paolo Ruggi -
136
E-TEST: Seismic Isolation and Thermal Noise Reduction for Next-Generation Observatories
The E-TEST prototype, developed for the Einstein Telescope—a next-generation gravitational-wave observatory, utilises a 100-kg test mass cooled to 20–25 K using radiative cooling techniques. This system achieves effective seismic isolation below 10 Hz while minimising thermal noise, a key challenge for high-precision measurements. Active isolation successfully mitigates low-frequency seismic disturbances, while the integration of cryogenic sensors and electronics allows for the monitoring of vibrational dynamics in the penultimate cryogenic stage.
Serving as a crucial research and development platform, E-TEST advances suspension technologies essential for the Einstein Telescope's technical design. The study also examines the performance of electrostatic actuators in this context and explores the impact of air damping at cryogenic temperatures. Furthermore, an adapted method for determining the mechanical quality factor, which is related to thermal noise, is presented. This method drives the resonator at resonance with constant amplitude to measure the required drive amplitude for estimating the quality factor, offering a continuous, real-time assessment with stable signal-to-noise ratio, unlike traditional free-decay techniques. These advancements highlight E-TEST’s contribution to improving future gravitational-wave detectors.
Speaker: Hemendra Singh -
137
ETIC - Laboratory of Architecture and Territory
The Laboratory of Architecture and Territory, whose members are all architects and researchers from the Department of Civil, Environmental Engineering and Architecture (DICAAR) of the University of Cagliari, Italy, explore the potential of designing research infrastructures and their spatial components by considering territorial systems. in recovering the material and immaterial value of a mining landscape as peculiar as that of Sos Enattos, Lula (Sardinia) – candidate site to host the Einstein Telescope. Especially today, with knowledge intended as a crucial agent in orienting the ecological transition, ET represents a unique opportunity to rethink forms, figures and images associated with scientific progress. What is the role of architectural and urban design in reshaping the space of scientific infrastructures, its boundaries and the powerful connections with their hosting
territories?
The research activities are devoted to the accurate work of identification and possible enhancement of the multiple layers that characterize Sos Enattos as a peculiar landscape entity. In fact, mining sites are to all intents and purposes included in the notion of “landscape” that, in this case, is the result of a complex and stratified process of interventions on the soil converted into a productive and exploitable resource. In particular, the mining landscape of Sos Enattos is punctuated with architectural presences, isolated or in cluster form, coinciding with the surface infrastructure at the service of the underground mining activities. Such a territorial infrastructure represents a tremendous source of inspiration for developing new typological solutions and symbolic-expressive values.
Taking existing buildings as the testing ground of a broader strategy, preliminary design projects are currently under development.
Starting from an open and flexible program, where scientific research, dissemination and interaction with the general public coexist, these interventions are presented both as a “gateway” to the Einstein Telescope infrastructure and, most of all, as a pilot project for the territorial system identified with the future science park. Its design will be based on recurrent type of landscaping and architectural interventions, including technically sustainable solutions, able to connect life above the ground with the scientific universe underground.Speakers: Fabrizio Pusceddu (Università di Cagliari - Dipartimento di Ingegneria Civile, Ambientale e Architettura), Marco Moro (Università degli Studi di Cagliari - DICAAR), Massimo Faiferri (Università di Cagliari), Silvia Mocci (Università degli Studi di Cagliari), Stefano Cadoni (Università degli Studi di Cagliari DICAAR), Stefano Mais (DICAAR, Università degli Studi di Cagliari) -
138
GALILEO Infrastructures for Einstein Telescope: Advanced Quantum Optics Technologies and Magnetic Emission Characterizations
The Italian Einstein Telescope Infrastructure Consortium (ETIC) is an initiative led by INFN aimed at establishing a network of laboratories crucial for the future Einstein Telescope gravitational wave interferometer, alongside characterization efforts for the Sos-Enattos site in Sardinia, Italy. This poster will present the GALILEO project for the Einstein Telescope, planned to be set up at INFN-Genova and the University of Genova. The project seeks to establish a new laboratory for the development of advanced quantum optics technologies and a new facility for the characterization of magnetic emissions from critical interferometer components.
Speakers: Barbara Garaventa, Dr Federico Armato (UNIGE - INFN Genova) -
139
Innovative On-Site Continuous Production and Welding of the Einstein Telescope Vacuum Pipes
The Einstein Telescope will consist of 120 km of vacuum pipes with a diameter of 1 m to achieve the required design sensitivity. The BeamPipes4ET project introduces an innovative production concept for these vacuum pipes by manufacturing them on-site in the tunnels through a continuous process using coils of sheet metal. This minimizes the transportation needs - forming the key concept of this project. Additionally, the project investigates the use of seamless flanges for ultra-high vacuum applications and explores laser beam welding under mobile vacuum. These approaches enhance reliability while reducing labor costs, welding efforts, and finishing work. This poster presents the current status and ongoing activities of the BeamPipes4ET project.
Speaker: Ms Charlotte Benning (RWTH Aachen University) -
140
Modal analysis of Q-factor measurements of cryogenic suspensions for ET-LF in GRAVITHELIUM
The ERC project GRAVITHELIUM aims to investigate the dissipative behaviour of full-scale suspensions used to cool-down the cryogenic core optics in ET-LF. Two possible suspension concepts are currently considered, using either monocrystalline suspension fibres made of silicon or sapphire, or titanium suspension tubes filled with static He-II. The dissipative behaviour of these suspensions is characterized by the mechanical Q-factor. It can be measured by the ring-down method, exciting the suspensions to resonance vibrations on the nanometre scale and analysing the decay time. Modal analysis has concluded that the second and the third modes of the suspensions are measurable, which occur between 40 Hz and 160 Hz. In this frequency range, the experimental set-up is designed to keep the extrinsic dissipation below the intrinsic dissipation of the suspension. We present the design approach for the different types of suspensions.
Speaker: Enes Turkic (Karlsruhe Institute of Technology) -
141
Predicting gravitational wave signals in cosmological simulations of galaxy formation with Arepo-GW
We present a new method for incorporating gravitational wave (GW) sources into cosmological simulations of galaxy formation. Our approach, implemented in the moving-mesh code Arepo, associates the properties of merging binary systems – black hole-black hole, black hole-neutron star, and neutron star-neutron star – with star particles representing a single stellar population (SSP) in cosmological simulations. This association is performed through stochastic sampling of binary merger events, as predicted by state-of-the-art stellar evolution models (e.g., MOBSE or SEVN), and is based on the local properties of the SSP, such as metallicity and age.
Our method can operate in two modes: (i) on-the-fly, generating GW events as a galaxy formation simulation progresses, and (ii) in post-processing, tracking back the evolution of stellar particles based on their properties starting at any given redshift for which a snapshot is available. Recently, we applied this approach to the flagship simulation of the Millennium-TNG suite – one of the largest hydrodynamical galaxy formation simulations to date, with a box size of 0.5 Gpc/h – and we will present the properties of the resulting GW event catalogue. Our tool can be extended to also process snapshots beyond the native Arepo format, making it broadly adaptable. This flexibility enables more realistic GW event predictions, which can be used to validate analysis pipelines for cosmological constraints using dark sirens, among other applications.Speakers: Federico Marinacci (University of Bologna), Prof. Marco Baldi (University of Bologna) -
142
Study of the Virgo Superattenuator vertical control to improve low frequency performance
Gravitational waves (GWs) detectors have been upgraded over time to enhance their sensitivity, pushing the limits imposed by their infrastructure.
Next generation observatories, Einstein Telescope and Cosmic Explorer, are currently under design, aiming for significant improvement in sensitivity that can have significant implications in scientific research. Among them, the possibility of detecting high-redshift compact object mergers, enhancing signal-to-noise ratios for spinning neutron stars and the stochastic background, and enabling early warnings for multimessenger observations by lowering the minimum detectable frequency.Seismic noise remains a major challenge for detecting GWs below 10 Hz, as ground vibrations propagate to the mirrors. To optimally operate the detector, it is also very important to minimize the mirrors’ Root-Main-Square (RMS) residual motion. In Virgo, the solution developed to mitigate seismic noise led to the Super-Attenuator (SA), which provides passive seismic isolation for frequencies above 4Hz. However, seismic noise is amplified in the range of 0.1÷3 Hz, increasing the RMS motion with respect to the ground.
This work aims to develop a control system to damp the SA resonances and reduce the mirror’s RMS residual motion, through a combination of theoretical modelling, simulation, and practical control strategies.
A Python simulation of the SA’s temporal evolution has been implemented by employing state-variable models and ARMA techniques. Full-state feedback has been designed, employing pole placement techniques to manipulate system dynamics and achieve the desired performance in the vertical degree of freedom of the Signal Recycling (SR) tower.
The model is expected to be tested during the April-May commissioning break, where the control system's performance will be assessed.Speaker: Maria Antonietta Palaia (Università di Pisa and INFN-Pisa) -
143
Thermal effects on the Input Test Mass (ITM) of the Einstein Telescope High-Frequency arm
Thermal gradients in the Input Test Masses (ITM) introduce optical aberrations that pose a critical challenge for both current and next-generation gravitational wave (GW) interferometers, significantly affecting their stability and sensitivity. Using the temperature map obtained through finite element analyses, the optical path difference (OPD) caused by thermal lensing and the deformation of the high-reflecting (HR) surface are computed. The impact on the Fabry-Perot cavity is then assessed, and the potential for thermal compensation through a laser actuation system is evaluated preliminarily.
Speaker: Ivan Di Antonio (INAF - Osservatorio Astronomico d'Abruzzo) -
144
Using a tunable Hartmann wavefront sensor for aberration measurements in ET-HF
In ET-HF it is expected that there will be optical aberrations due to thermal deformation of test masses. The aberrations will influence the sensitivity but less is known about the expected aberration order of magnitude or shape. In our study, we tackle the optical measurement of the aberration by simulating the optical read-out via a Hartmann wavefront sensor. We study the sensor components and propose an effective and customized tuning of, both, the measurement range and the sensitivity. The tuning is based on the exchange and position of the Hartmann plate without any change of the optical path. We demonstrate our design approach on a test aberration.
Speaker: Andreas Mathwieser (Fraunhofer IPT) -
145
A compact interferometric sensor for precise sensing of displacement below 1kHz based on novel glass technologies
The Einstein Telescope, as a third-generation gravitational wave detector, aims to improve the sensitivity of the detection band in the low-frequency region over existing gravitational wave detectors. For this, displacement sensors that provide high sensitivity between 100 mHz and 200 Hz are required for seismic isolation, and the scientific community is striving to increase their sensitivity by investigating novel sensing techniques. We demonstrate a heterodyne interferometric displacement sensor design that aims to be compact while achieving a sensitivity in the sub-picometer region in the mentioned frequency range. Our sensor receives its compact nature by decoupling the interferometric readout and sensing units using a polarisation-maintaining optical fibre. By sending both the reference and the test beam through the same fibre, we can reduce the optical components in the sensing unit to a polarising beam splitter and a mirror. At the same time, no electronics are required in the sensing unit at all. We present measurements from our tabletop sensor setup achieving a sensitivity better than $1 pm/ \sqrt{Hz}$ between 3 Hz and 600 Hz and better than $30 pm/ \sqrt{Hz}$ down to 100 mHz. In addition, we show our sensor's nonlinear phase contributions are smaller than $\pm 5nm$ when the test mass is moved over more than 5.4 µm. Using novel glass technologies, we aim to make our sensing unit even more compact. With the development of a meta-structured sensor head that provides the properties of a polarising beamsplitter, a high reflective mirror and a fibre collimator at the same time, parts of the classical optics can be replaced with just a single glass element. By splicing the fibre directly on the glass body, we would get an ultra-stable monolithic fibre sensor head assembly. We show a first prototype of the metastructure, which is spliced directly onto a fibre and acts like a flat lens without yet offering the properties of a polarising beam splitter. Based on our data, we are convinced that our current design already represents a compact displacement sensor that can be used to increase the sensitivity of a third-generation gravitational wave detector in the low-frequency regime. The meta-structure currently under development aims to make the sensor head even more compact while representing a unique fibre-coupled assembly to split light depending on the polarisation state into a reference and sensing beam within a monolithic glass body.
Speaker: Johannes Bäuerlein (Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Institute for Gravitational Physics of the Leibniz Universität Hannover) -
146
A robust cosmic standard ruler from the cross-correlations of galaxies and dark sirens
Observations of gravitational waves (GWs) from dark sirens measures source locations and distances, whereas galaxies have precise angular positions but no direct measurement of their distances -- only redshifts. By cross-correlating GWs from binary black hole mergers, in spherical shells of luminosity distance DL, with galaxies in shells of redshift z, we project a direct measurement of the Hubble diagram DL(z). Since this standard ruler relies only on the statistical proximity of dark sirens and galaxies, our method (dubbed "Peak Sirens") is essentially model-independent.
We make forecast for the method for the observation run 5 of LIGO-Virgo-KAGRA (LVK), as well as for the third-generation observatories Einstein Telescope and Cosmic Explorer. We employ thousands of full-sky light cone simulations with realistic numbers for the tracers, and include masking by the Milky Way, lensing and inhomogeneous GW sky coverage.
We show that future third-generation GW detectors can achieve sub-percent uncertainties in H0 assuming LCDM, and 3% in a more flexible w0waCDM model. The method also shows remarkable robustness against systematic effects such as the modeling of non-linear structure formation.Speaker: Prof. Riccardo Sturani -
147
Adsorption and Desorption on Cryogenic Mirror Surfaces in Vacuum
In-situ monitoring and a good understanding of adsorption and desorption processes on cryogenic mirror surfaces are essential for the LF interferometers of ET and for ET-Pathfinder. A working group with members from UM, TNO and KIT work on a test setup focusing on two technologies for the monitoring of the growth of monolayers on cold surfaces, ellipsometry and microbalances. This poster provides an update of the work and planned measurements. After establishing reliable and reproducible monitoring techniques, this setup can also be extended to test possible in-situ cleaning methods of mirror surfaces at cryogenic temperatures.
Speaker: Dr Adrian Schwenck -
148
Advancements in Real-Time Control Systems and Sensing Technologies for Seismic Isolation in Future Gravitational-Wave Detectors
The pursuit of next-generation gravitational-wave detectors, such as the Einstein Telescope, with its ambitious goals for sensitivity, places extreme demands on the complex systems controlling the position of suspended mirrors. Operating in underground environments with exceptionally low seismic noise and targeting an extended bandwidth from low to high frequencies, these systems require major advancements in real-time control and sensing technologies. At INFN Pisa, we are investigating several solutions to address these challenges.
In terms of electronics hardware, we are pursuing two primary strategies. Firstly, we are improving consolidated DSP-based architectures, extending flexibility with FPGA modules and optimizing data converters. This will also support the upcoming upgrades to the current generation of detectors. Secondly, we are exploring the potential of GPU-accelerated architectures, including integration of machine learning techniques for controls and data processing tasks. The feasibility of this solution is under evaluation on a GPU-FPGA testbed, using direct memory access techniques to reduce latency, a critical parameter for reliable operation.
In parallel, we are progressing with the development and testing of position and inertial sensors, particularly focusing on the evaluation of optical readout mechanisms for a newly designed accelerometer. A tabletop test system based on a fiber-optic interferometric setup is used to assess performance, aiming for novel solutions to improve the sensitivity of current sensor technologies.
This contribution would like to present the status of these ongoing R&D efforts at INFN Pisa, along with preliminary results from experimental testbeds.Speaker: Paolo Prosperi (INFN Sezione di Pisa) -
149
Can we identify primordial black holes? Analysis and physical implications of candidate subsolar gravitational-wave events
The detection of a subsolar object in a compact binary merger is regarded as one of the smoking gun signatures of a population of primordial black holes (PBHs). We critically assess whether these systems could be distinguished from stellar binaries, for example composed of white dwarfs or neutron stars, which could also populate the subsolar mass range. At variance with PBHs, the gravitationalwave signal from stellar binaries is affected by tidal effects, which dramatically grow for moderately compact stars as those expected in the subsolar range. We forecast the capability of constraining tidal effects of putative subsolar neutron star binaries with current and future LIGO-Virgo-KAGRA (LVK) sensitivities as well as next-generation experiments, such as Einstein Telescope. We show that, should LVK O4 run observe subsolar neutron-star mergers, it could measure the (large) tidal effects with high significance. Also, we show possible consequences of the detection of such important candidates, both from the cosmological and the nuclear-physics points of view.
Speaker: Francesco Crescimbeni -
150
Characterisation of Crystalline Silicon Fibres produced by IKZ Berlin for the ET-LF payload
With the plans for ET-LF to operate at cryogenic temperatures, there is a need for advanced, low-noise crystalline suspension systems to reach the required sensitivity goals. Crystalline silicon is a promising candidate for suspension elements due to its favourable properties at cryogenic temperatures, including a high quality factor, high thermal conductivity and advantageous thermoelastic properties. It has been shown that these properties, as well as mechanical strength, are dependent on the surface quality and fabrication process of the material. Therefore, an optimised production process for crystalline fibres is crucial, along with thorough investigation of their properties. In this study, we present the characterisation of crystalline silicon fibres grown using the float-zone technique by the Institut für Kristallzüchtung (IKZ) Berlin. We examine material purity levels, crystal orientation, and diameter uniformity, alongside in-depth mechanical tensile strength testing via along-axis linear drive and four-point bending techniques. Additionally, we evaluate the thermal conductivity of the fibres to ensure sufficient heat extraction from test masses. These initial results demonstrate the potential feasibility of producing high-quality silicon fibres and indicate that, with further optimisation and characterisation, they have the potential to achieve the necessary low thermal noise performance, reinforcing silicon's suitability as a candidate material for next-generation gravitational wave detectors.
Speaker: Ardiana Nela -
151
Einstein-Podolsky-Rosen conditional squeezing for future Gravitational-Wave detectors
The current measurement scheme for a broadband quantum noise reduction in GW detectors relies on 300 m long and detuned filter cavities, that has been stunningly proven in Advanced LIGO and successfully commissioned in Advanced Virgo, for the run O4.
Nevertheless, they add infrastructural complexity and optical losses on top of an already large instrumental apparatus. Moreover, ET will need longer cavities to effectively achieve its unprecedented sensitivity. The present plan is to build a 1-km-long filter cavity for ET-HF, and two 5-km-long cavities for ET-LF.
Several proposals have been raised in the past years to avoid the presence of filter cavities, while attaining similar or better performances in terms of quantum noise suppression. One of the possible alternatives is represented by the conditional squeezing scheme, where a pair of EPR-entangled squeezed beams propagate in the interferometer, and one of them sees it as a filter cavity. Their parallel homodyne detection and the application of an optimal filter allow for broadband quantum noise reduction.
Despite several experimental demonstrations, the evidence for EPR effect in the audio frequency band of interest for GW detectors is still lacking, and this is the scientific goal of the ongoing experiment presented in this contribution. In particular, the implementation of an analytic simulator is highlighted here. Its purpose is to assess the real feasibility of EPR scheme in GW detectors, accounting for optical losses and decoherence effects.Speaker: Francesco De Marco (La Sapienza University of Rome and INFN Roma1) -
152
Exploring Short Gamma-Ray Bursts: afterglow insights from the S-BAT4 extended sample
In the context of Gamma-Ray Bursts (GRBs) astrophysics, the class of short GRBs is particularly fascinating since they are expected to be produced in compact binary mergers, and to be associated with gravitational wave (GW) events. Double neutron star or neutron star-black hole binaries likely generate another electromagnetic transient, known as Kilonova (KN). As such, with the present and future planned GW observing runs we expect to observe more events with coincident detections in addition to GW170817/GRB170817A/AT2017gfo, the only observation of a short GRB, a GW, and a KN obtained so far. The knowledge of the population of short GRBs is thus essential for proper analysis and characterization of these events and a deeper understanding of the underlying physics.
In the talk, I will present a carefully selected sample of short gamma-ray bursts (SGRBs) observed with the Neil Gehrels Swift Observatory from Nov. 2004 to Dec. 2022, namely the S-BAT4 extended sample. GRBs selection criteria include bright events, prompt satellite repointing, and favorable observing conditions for the redshift determination from the ground. The sample consists of 51 events, 62% of which have a spectroscopic redshift measure, and for other 17% a photometric \textit{z} has been determined. Such flux-limited sample minimizes any redshift-related selection effects and can provide a robust base for the study of the energetics, redshift distribution, and environment of the Swift bright population of SGRBs. The prompt and afterglow emissions have been analyzed by computing the rest frame properties of the bursts in terms of energetics and luminosity. In particular, the analysis of the afterglow properties of the sample allowed us to derive and classify 35 and 12 rest-frame light curves in the X-rays and in the optical-near infrared bands, respectively. The majority of the light curves reveal a different evolution in the X-rays and in the optical band, at least at early times. In addition, the comparison of afterglow luminosity at different rest-frame times with prompt emission features suggests a different origin for the X-ray and optical emission, at least during the early phases, with the presence of additional components (e.g. late time activity of the central engine) on top of the pure afterglow emission, which dominates at later times. The large statistics of the sample also gives the opportunity to study the intrinsic absorption properties of short GRBs. Their distribution has been found to be consistent with 0, with no events displaying significant local absorption.
The comparison with a sample of long GRBs (the BAT6 sample) built with similar criteria and of comparable size revealed the different nature of the events belonging to the two samples, and this will be a useful benchmark for a more detailed classification of GRBs that will be observed in the future.Speaker: Riccardo Brivio (INAF-OAB) -
153
Mergers of strange quark stars
We analyze GW190425 and GW170817 within a scenario in which strange quark stars (QSs) coexist with neutron stars. We will conclude that:
- GW190425 could be a QS-QS merger, producing a supramassive QS;
- a QS-QS merger produces a weak KN signal (which could have passed undetected in the case of GW190425);
- the material ejected in the post-merger is mostly flowing in the equatorial plane, leaving an empty cone around the rotation axis;
- it is therefore not impossible that a FRB was produced and detected in association with GW190425;
- if GW190425 produced a supramassive QS, GW170817 most likely produced a totally stable QS. A large fraction of its rotational energy could have been released by emission of GWs because QSs can develop large non-axisymmetric instabilities even in the presence of a small degree of differential rotation. In this way the main objection against the formation of a stable remnant can be addressed.
Obviously, in both cases ET could clarify immediately the fate of the merger by observing the ring-down signal.Speaker: Alessandro Drago (University of Ferrara) -
154
Stray light noise from dust particles falling inside Einstein Telescope beam pipes
High sensitivity optical measurements, such as those performed in interferometric Gravitational Waves detectors, are prone to stray light noise. Due to the high-quality optics used in the interferometers, light scattering may be dominated by the residual presence of particles. This can be an issue for the next generation detector Einstein Telescope as well as for the present LIGO and Virgo interferometers. It is therefore crucial to account for all possible light-dust interaction mechanisms and to estimate the noise they can generate.
In our work, we performed a detailed analysis of particulate contamination focusing, as a case study, on the beam pipes of Einstein Telescope. There are two main cases for light scattering by particulate contamination inside the beampipes: particles deposited on the baffles and particles moving in the beam pipe volume under vacuum. Here we report our latest results concerning this latter contribution. First, we determine how the field amplitude and phase fluctuations induced by falling particles crossing the arm cavity beam contribute to the detector’s strain noise. Then we perform Monte Carlo simulations to assess the impact of different cleanliness scenarios. Finally we study how installation procedures and general operations on beam-pipes can contribute in terms of dust contamination.
This study allows us to establish upper limits on the number and size of dust particles that can be tolerated detaching from the pipe surface, therefore setting constraints on the cleanliness of environments and installation procedures. Our results refer specifically to Einstein Telescope, but they can be extended easily to other ground-based interferometers.
Speaker: Andrea Moscatello -
155
Taming systematics in distance and inclination measurements with gravitational waves: role of the detector network and higher-order modes
Gravitational-wave (GW) observations of compact binaries have the potential to unlock several remarkable applications in astrophysics, cosmology, and nuclear physics through accurate measurements of the source luminosity distance and inclination. However, these parameters are strongly correlated when performing parameter estimation, which may hamper the enormous potential of GW astronomy. We comprehensively explore this problem by performing Bayesian inference on synthetic data for a network of current and planned second-generation GW detectors, and for the third-generation interferometer Einstein Telescope (ET). We quantify the role of the network alignment factor, detector sensitivity, and waveform higher-order modes in breaking this degeneracy. We discuss the crucial role of the binary mass ratio: in particular, we find that ET can efficiently remove the error in the distance as long as the compact binary is asymmetric in mass.
Speaker: Adriano Frattale Mascioli (Virgo) -
156
Testing Real-Time Noise Prediction Techniques
Prediction and mitigation of noise can increase the sensitivity of future gravitational wave detectors like the Einstein Telescope. These mitigation techniques could reduce noise from sources that can be independently measured, like seismic, electromagnetic, or acoustic disturbances. Wiener filters are a common technique that has been tested in current detectors. We are exploring the potential of other model-independent techniques to improve noise suppression. In a small-scale interferometer, we observe improvements beyond the Wiener filter performance for adaptive filtering techniques and deep-learning approaches. Furthermore, we are investigating the applicability of these techniques in real-time.
Speakers: Markus Bachlechner (RWTH Aachen University), Tim Kuhlbusch (RWTH Aachen University) -
157
The Superattenuators for the CAOS Project
The CAOS (Centro per Applicazioni sulle Onde gravitazionali e la Sismologia) facility is currently under construction in Perugia, Italy. It will host a short Fabry-Perot cavity to carry out dedicated R&D on seismic attenuation systems for ET, specifically enabling the development of two AdV-like Superattenuators (SAs), a technology that represents the ET reference solution as envisaged in its conceptual design.
Both SAs will be taller than those of AdV+ and they will incorporate new technologies, such as new Magnetic Anti-Springs. However, during the conceptual design phase, we adopted slightly different approaches for the two SAs. The one called BS will be conceptually very similar to the AdV+ SA, whereas the other, named EE, will introduce new concepts and features, including innovative crossbars for seismic filters, a Disk 0, and an active platform with enhanced "feet".
The mechanical design is currently in progress thanks to a collaborative effort between INFN Pisa, INFN Perugia, and UNIPG. Meanwhile, the manufacturing of mechanical components has already begun at Galli & Morelli's workshop.Speaker: Dr Leonardo Lucchesi (INFN Pisa) -
158
Tracing and damping ghost beams for Virgo in O5: a lesson for ET
An ideal design of the Einstein Telescope would assume perfect coatings and alignment, and would foresee no polarization leakage. However, non-idealities, such as residual reflectivity of antireflection coatings or residual transmissivity of mirrors, a number of “ghost beams” are generated. These are beams that should nominally not exist, serve no purpose and are not directly handled and routed in the ideal optical layout of the interferometer. If unstopped, they can easily spoil the sensitivity of the detector by generating additional interfering signals and generically causing stray light noise. To obtain a realistic design, it is mandatory to take into account the presence of those unwanted beams in a ray tracing simulation, useful for planning adequate measures to block all ghost beams before they become harmful.
We report on our recent experience with Virgo in the context of the new Stable Recycling Cavities: in particular, we show a ghost beam ray tracing study for the Power and Signal Recycling cavities, developed with the commercial software Zemax. We discuss how our case studies offer insights for planning ray tracing simulations for ET.Speaker: Francesco Flocco (INFN) -
159
Agile frequency synthesis with distributed synchronization
In the current Virgo setup, quantum noise reduction is achieved by injecting squeezed vacuum states in the interferometer dark port. For their generation and phase stabilization with respect to the interferometer carrier, low-noise phase locked loops (PLL) and direct digital synthesizers (DDS) are used. An RF-mixer based architecture is under investigation for the development of an alternative frequency synthesizer with improved close-in phase noise, which may also be suitable for Einstein Telescope. Such a circuit essentially combines the best of PLL and DDS technologies, allowing phase alignment of the generated signal in relation to a given reference clock, together with strong “jitter-cleaning” capabilities and agile frequency adjustment. The deployment of a White-Rabbit based distributed synchronization system will make it possible to address synchronization of RF sources across the detector with adequate frequency stability.
The talk is intended to showcase the principle of operation of the circuit, expose the main design challenges and report some preliminary measurements on a demonstrator setup. Limitations of the current approach will then be exposed, concluding with some remarks on further developments.Speaker: Marco Toffano (INFN Padova) -
160
BNS mergers as multi-messenger sources: end-to-end numerical modeling in preparation for the ET era
The advent of the Einstein Telescope (ET) will revolutionize our understanding of binary neutron star (BNS) mergers, with a huge number of gravitational wave (GW) detections expected every year, spanning about 10 billion years of cosmic history. As demonstrated by the GW170817 event, the greatest scientific potential is held by multi-messenger observations combining the GW signal with the prompt and afterglow emission from a gamma-ray burst (GRB) jet, and, for nearby events (within redshift 0.5), the radioactively-powered kilonova (KN).
Current understanding of an event like GW170817 is however limited by the lack of a unified theoretical framework directly connecting a specific BNS merger and corresponding GW emission with the emerging relativistic jet piercing through the post-merger environment and ultimately powering the GRB. As a consequence, also the KN is typically modeled without taking into account the strong constraints coming from the GRB-related signals. To fully leverage the opportunities offered by ET in this context, it is necessary to build such a unified theoretical framework.
In this talk, I will discuss recent progress in developing a consistent end-to-end description by combining numerical simulations that encompass very different scales, from the merger process itself to the production of an incipient jet piercing through the post-merger environment and its propagation up to the scales relevant for shaping the associated electromagnetic emission.Speaker: Dr Andrea Pavan (INAF-Osservatorio Astronomico di Padova) -
161
Constraining the features of the BBH mass distribution through population synthesis simulation
The first direct detection of gravitational waves (GWs), back in 2015, marked the beginning of a new era for the study of compact objects, and the upcoming next-generation detectors, such as Einstein Telescope (ET), are expected to add hundreds of thousands of compact binary coalescences to the list. We discovered up to 90 GW signals, from which we were able to put some constrains on the phenomenon leading to the formation, the evolution and the eventual merger of binary systems.
However, the processes occurring during the evolution of such systems exhibit degeneracies, making it challenging to obtain individual constraints.
In this talk, I will show the result we obtained when we tried to disentangle such degeneracies, performing population synthesis simulations under various assumptions and trying to reproduce the distribution we observe from the data collected by LVK.Speaker: Cristiano Ugolini (GSSI, SISSA) -
162
Dark sirens number counts with the Einstein Telescope: cosmological forecasts and astrophysical modelling
The present generation of interferometers has demonstrated that gravitational-wave observations, even in the absence of electromagnetic counterparts, i.e. dark sirens, can serve as an independent method to investigate the Hubble tension. However, while the proposed designs for the Einstein Telescope (ET) can produce astonishingly precise $H_0$ measurements, it has been shown that incorrect astrophysical modeling in dark sirens methods can bias our estimates, hence effort must be put into studying the star binaries population properties as progenitors of these events.
In this talk, I will introduce a number counts technique to derive $H_0$ solely from gravitational-wave data, bypassing assumptions about black hole masses or external galaxy catalogs. By comparing the expected number of dark sirens to those actually detected, we gain a powerful handle on cosmic expansion, particularly in view of ET’s projected capabilities, expected to significantly increase the gravitational-wave event sample.
I will discuss our refined models on merger rate evolution, star formation histories, and binary population synthesis (via the SEVN code) and then highlight the importance of the common envelope (CE) phase and its effects on our astrophysical models and on $H_0$ constraints. I will showcase results for the ET with number counts only and in different CE models and compare the results for the triangular vs. 2L design sensitivities.
Speaker: Mr Giovanni Antinozzi (SISSA - Scuola Internazionale Superiore di Studi Avanzati) -
163
Femtometer-precision displacement sensing with heterodyne cavity-tracking
Precise displacement sensing with femtometer or sub-femtometer readout noise at frequencies below $10\,\mathrm{Hz}$ is extremely beneficial for the ET active isolation systems. Here, we present a laser interferometric sensor, named heterodyne cavity-tracking, designed for high-precision relative displacement readout. The scheme utilizes a heterodyne-stabilized optical cavity, incorporating the proof mass, and retrieves displacement via heterodyne interferometry. The combination of the optical cavity and frequency readout pushes the achievable sensitivity into the sub-femtometer regime. The frequency readout and laser frequency control are accomplished using an ultra-high bandwidth phase-locked loop (PLL) phasemeter, which can directly track signals up to $2\,\mathrm{GHz}$, allowing for a fringe-scale operating range in displacement sensing.
Initial experiments have demonstrated an overall displacement readout noise floor of less than $20\,\mathrm{fm/\sqrt{Hz}}$ for frequencies above $5\,\mathrm{Hz}$ and a maximum motion of about $0.15\,\mathrm{µm}$, achieving a dynamic range of six orders of magnitude in displacement sensing.
Speaker: Mr Shreevathsa Chalathadka Subrahmanya (University of Hamburg) -
164
Galaxy Catalog Incompleteness Effects in Standard Siren Cosmology
Galaxy catalogs can be combined with gravitational wave observations to provide cosmological constraints through the dark siren method. However, host galaxies may be missed in the catalogs due to observational effects, potentially weakening the constraints and introducing systematics. At the same time, galaxy catalogs can include galaxy properties - such as the stellar mass - that can be incorporated as hosting probability weights. We extend the standard siren method including completeness and weighting effects and include them in CHIMERA, a hierarchical Bayesian pipeline for joint cosmological and astrophysical population parameter constraints. We generate a mock catalog representative of LIGO-Virgo-KAGRA O5 scenario. We quantify how catalog completeness and host galaxy probability assumptions ultimately impact on H0 constraints, providing key metrics to inform the design of future electromagnetic and gravitational wave facilities. This framework represents a significant advancement in preparing for wide-field spectroscopic surveys, such as WST, which could play a crucial role in gravitational-wave cosmology.
Speaker: Nicola Borghi -
165
MezzoCielo: an ultra-wide field telescope for all-sky transient surveys
MezzoCielo, meaning "half of the sky," represents one of the most advanced developments in the class of all-sky survey telescopes. This revolutionary design is built around a fully spherical refractive optical element, filled with a highly transparent, low-refractive-index liquid, and surrounded by a large array of identical cameras. By leveraging this unique optical architecture, MezzoCielo achieves an unprecedented field of view, continuously observing an area of the sky exceeding ten thousand square degrees.
The optical design and the high-cadence monitoring capabilities makes MezzoCielo ideal for the detection and early localization of transient astrophysical phenomena pushing at the limit the capabilities of ground-based optical surveys. MezzoCielo proposes to be the optimal companion for multi-messenger astrophysics, looking forward to the next-generation gravitational wave observatory, the Einstein Telescope (ET).Speaker: Demetrio Magrin (INAF - Osservatorio Astronomico di Padova) -
166
Mimicking the Luminosity Function Evolution
UpGLADE is an upcoming extensive galaxy catalogue which will include more than a billion objects from various non-independent surveys, providing redshift information, which is fundamental for gravitational-wave (GW) cosmology – particularly for Hubble constant inference using dark sirens and galaxy catalogue. Moreover, UpGLADE will play a crucial role in multi-messenger astronomy by supporting GW follow-up campaigns and targeting possible electromagnetic counterparts.
Addressing the intrinsic incompleteness of galaxy catalogues is a key challenge in the statistical approach to GW cosmology, although assessing the completeness of UpGLADE is not trivial because it consists of multiple flux-limited samples covering different patches of the sky. This problem is tackled by analysing the luminosity function of the cross-matched catalogue using the Vmax method, which has been specifically adapted to account for its heterogeneity. The study reveals a behavior that could be interpreted as an evolution of the luminosity function over different redshift ranges. Our work aims to evaluate the impact of redshift uncertainties in the UpGLADE luminosity function, potentially mimicking its evolution.
Preliminary results suggest that redshifts error models may introduce systematic biases in the derived luminosity function, with implications for cosmological analyses. These findings motivate the use of a mock catalogue to interpret our results and provide a comparative framework, ultimately enhancing the reliability of UpGLADE for getting unbiased estimates of the Hubble constant.Speaker: Maria Lisa Brozzetti (Università degli Studi di Perugia - Ligo-Virgo-Kagra and ET Collaboration) -
167
R&D activity to develop a passive mitigation strategy for electrostatic charging in future gravitational wave detectors
Electrostatic charging on the surfaces of the optical elements is a limiting noise source for gravitational wave detectors (GWD) already at room temperature. The charge accumulation has been already observed in LIGO and possibly in Virgo.
The electrostatic charging mechanism of the mirrors may be mainly caused by local electrostatic (LIGO) or electro-magnetic (Virgo) controls.
Another possible mechanism may be due to the ionic pumps that may release low energy electrons.Such potential electron sources are located in the mirrors’ towers and distributed along the beampipes to grant the required Vacuum in the detector.
To cure such issue, Ligo developed a mitigation method, based on exposing the mirrors to few mbar of a N$_2$ plasma flux. This method cannot be used on a mirror at cryogenic temperature due to the significantly thick condensed gas layer that would inevitably be formed on mirrors. Some other strategies to actively remove charges from optics at cryogenic temperature are currently under study. However, the development of new technologies to passively mitigate electrostatic charging may help preserving the performances envisaged by future GWD.Here we present our collaboration R&D activity to develop a passive mitigation strategy for the electrostatic charging based on electrostatic collectors that, opportunely polarized at an optimized voltage, can catch electrons coming from the ion pumps, hence reducing one of the possible sources of such detrimental effect.
Speaker: Dr Marco Angelucci (INFN - LNF) -
168
The Collimation of Relativistic Jets in Late Post-Neutron Star Binary Merger Simulations
The gravitational waves from the binary neutron star merger GW170817 were accompanied by a multiwavelength electromagnetic counterpart, which confirms the association of the merger with a short gamma-ray burst (sGRB). The afterglow observations implied that the event was accompanied by a narrow, ~5°, and powerful, ~1e50 erg, jet. We study the propagation of a Poynting flux-dominated jet within the merger ejecta (kinematic, neutrino-driven, and magnetorotational instability turbulence-driven) of a neutrino-radiation-GRMHD simulation of two coalescing neutron stars. We notice that a postmerger low-density/low-pressure polar cavity, which arose due to angular momentum conservation, is crucial to letting the jet break out. At the same time, the ejecta collimates the jet to a narrow opening angle. The collimated jet has a narrow opening angle of ~4°-7° and an energy of 1e49-1e50 erg, in line with the observations of GW170817 and other sGRBs. Furthermore, we run a set of 2.5D high-resolution cylindrical RHD simulations where we inject a narrow, powerful jet into the post-merger phase of the BNS for different opening angles, luminosities, and times after the merger. We explore the case of an early launch of the jet at 0.1 s and a late launch at 1 s after the merger; the latter is consistent with the time delay of ≈ 1.74 s observed between GW 170817 and GRB 170817A.
Speaker: Dr Matteo Pais (INAF - Osservatorio astronomico di Padova (OAPD)) -
169
Unlocking Next-Generation Dark Siren Cosmology and General Relativity Tests with CHIMERA 2.0
Gravitational waves (GWs) from merging compact binaries have opened a new window into cosmology and fundamental physics, allowing precise tests of General Relativity (GR) and measurements of cosmic expansion. However, with the advent of future GW observatories, it is necessary to develop efficient and robust tools capable of handling the growing volume of data. In this talk, we present CHIMERA 2.0, a next-generation, GPU-accelerated, and fully differentiable pipeline for hierarchical Bayesian inference of cosmological, modified GW propagation, and population hyperparameters using dark sirens and galaxy catalogs. This code enables the analysis of several thousands of events, a crucial step for next-generation interferometers, such as the Einstein Telescope. Using CHIMERA 2.0, we analyze three mock populations of 300 dark sirens detected at SNR>20, assuming the nominal O5 sensitivity of the LIGO-Virgo-KAGRA network. Each population is characterized by a different value of the modified gravity parameter $\Xi_0$: 0.6, 1 (corresponding to GR), and 1.8. Taking advantage of the code's computational efficiency, we perform several Markov Chain Monte Carlo (MCMC) tests - analyzing ~5000 sources while varying MCMC configurations and galaxy redshift error assumptions. Using spectroscopic galaxy catalogs, we recover the fiducial $\Xi_0$ with accuracies of 22%, 7.5%, and 10% for $\Xi_0$ = 0.6, 1, and 1.8, respectively. At the same time, the precision on the Hubble constant $H_0$ is 2-7 times worse than when $\Xi_0$ is not marginalized. Photometric redshifts degrade the constraints by 3.5 times on average and fail to reduce parameter correlations that spectroscopic redshifts can resolve, underscoring the importance of future spectroscopic surveys to fully exploit the potential of standard sirens.
Speaker: Matteo Tagliazucchi
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Instrument Science (ISB) Plenary Room
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171
Measuring the mechanical and optical losses of coatings in cryogenic conditions using an optomechanical cavity
One of the most critical components of gravitational wave interferometers is their mirror test masses, as coating thermal noise is a primary limiting factor in the 20–2000 Hz frequency range. For this reason, one of the two nested interferometers composing Einstein Telescope (ET-LF) is designed to operate under cryogenic conditions. However, characterizing both mechanical and optical losses in mirror coatings under realistic conditions is challenging, especially at cryogenic temperatures, where thermo-elastic interactions between the coating and the substrate makes very hard to use standard characterization methods based on the measurements of mechanical Q factors of substrates coated with the materials to be characterized.
To address this issue, we propose an innovative experimental setup to measure optical losses and mechanical dissipation in freestanding coating membranes over a broad temperature range. By suspending the coating as a thin membrane, the thermo-elastic interactions between the coating and the substrates are minimized, which enables precise measurement of the coating's properties in the whole range between room temperature and few Kelvins.
The experimental apparatus features a low-vibration cryostat housing an optical cavity, along with piezo actuators for precise membrane positioning and alignment. The measurement consists in placing the membrane inside the resonator so that it couples with the stationary electromagnetic field circulating inside the cavity. The optical losses are determined by monitoring the finesse of the Fabry-Perot cavity as a function of membrane position along the optical axis. The mechanical dissipations are instead measured using the cavity as a sensitive transducer of the membrane vibration spectrum, with dissipation values extracted through a dedicated data analysis procedure.
Preliminary tests on low-stress silicon nitride (SiN) membranes confirm the functionality of the setup. In the next phase, we will test membranes made of materials with lower optical absorption than SiN to further refine our measurements. This will help in optimizing the apparatus and expanding instrumentation to enable more comprehensive studies.Speaker: Nicole Busdon -
172
Mitigation of point defects and residual non-axysimmetric aberrations on the high- reflectivity surface: challenges for the future generation test-masses
The increasing power levels injected into interferometric gravitational wave detectors have highlighted the impact of localized defects on the high-reflectivity (HR) surfaces of the main optics. These defects, originating from coating inhomogeneities, substrate imperfections, or localized absorbers, can degrade detector performance by introducing aberrations in the optical wavefront, leading to mode mismatches, loss of stored power, and reduced interferometer sensitivity.
As next-generation detectors such as ET-HF aim for circulating powers of up to 3 MW, addressing these issues requires an advanced wavefront control system capable of directly compensating for distortions on the HR surface. Building on studies carried on within the Advanced Virgo detector, a new actuator has been developed to correct axisymmetric aberrations and other residual distortions on the mirror surface, providing a more flexible and comprehensive approach compared to previous correction methods. The system modifies a binary mask responsible for generating the corrective pattern, allowing for precise compensation of a broad range of optical defects.
This talk will present an overview of wavefront distortions caused by localized defects, the design and operational principles of the new actuator, and its potential applications in future gravitational wave detectors. Initial results from correction tests carried on at the TeTIS facility at Roma Tor Vergata will be discussed, along with future challenges and strategies to further improve interferometer performances.
Speakers: Luciano Antonio Corubolo (Università degli studi di Roma Tor Vergata; INFN Roma Tor Vergata), Maria Cifaldi (Tor Vergata-INFN) -
173
Study of substrate and coating birefringence
At the Department of Physics and Earth Sciences at the University of Ferrara we have a sensitive polarimeter for birefringence measurements of both substrates and coatings. In the configuration for substrate measurements the polarimeter is based on two co-rotating half-wave plates with the sample between them. The induced time dependent ellipticity signal is then extracted using a heterodyne technique. A simple modification of the transmission scheme is implemented during reflection measurements. The sample can be scanned in 2D to extract birefringence maps both in transmission and in reflection. The sensitivity in optical path difference is $\lesssim 10^{-12}$ m. Results for different silicon samples (for substrates) with crystal orientations 110 and 100 will be shown along with coatings measurements.
Speaker: Guido Zavattini (University and INFN - Ferrara) -
174
Core optics discussionSpeaker: Core optics chairs
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175
Updated Stray Light Induced Noise Simulations in the Einstein Telescope main Arms
We present an updated estimation of the noise induced by scattered light inside the main arms of the Einstein Telescope (ET) gravitational wave detector. Both ET configurations for high- and low-frequency interferometers are considered. The new studies include the cryotrap areas close to the main mirrors, consider both 10km and 15km arms, and explore possible mis-alignments of the laser beam inside the cavity. As it is already the case in the existing experiments, baffles are used to mitigate and suppress the noise inside the vacuum tubes. New improved simulations are employed including the presence of the baffles and their serrated edges. We propose updated baffle layouts for ET and re-compute the remaining scattered light noise contribution to ET sensitivity.
Speakers: Marc Andrés-Carcasona (IFAE), Mario Martinez -
176
First demonstration of tunable coherence in a power-recycled Michelson
As straylight is an important limitation for the sensitivity of gravitational wave detectors, we investigate new laser operation concepts and interferometer topologies for a more straylight-resilient detector configuration.
Our main focus is the use of tunable coherence realized by phase modulation following a pseudo-random-noise (PRN)-sequence on the interferometer laser. This breaks the coherence of the delayed straylight reducing its intrusive impact with the remaining coherence length only depending on the PRN frequency. Thus, effectively realizing a pseudo white-light interferometer with tunable coherence length.
In addition to our successful concept demonstration in a Michelson interferometer and optical cavities individually, we effectively reduced the resonant enhancement of these cavities to a delays in the $\mu$m range.
Now, we present first results from a power-recycled Michelson at increased PRN frequencies up to 10 GHz reducing the coherence down to only several wave lengths.Speakers: Daniel Voigt (University of Hamburg), Oliver Gerberding (Universität Hamburg, Institut für Experimentalphysik) -
177
Quantum paths for ET: challenges of quantum noise and alternative detector configurations
Quantum noise is one of the main limitations to sensitivity in both the low- and high-frequency interferometers of ET. Reaching the design sensitivity requires the use of frequency-dependent squeezing, which relies on long filter cavities and minimizing losses throughout the entire interferometer. Achieving this is challenging, both technologically and fundamentally. However, considering the decades-long operational timeline of ET, we can imagine significant improvements in these areas, potentially enabling the use of even more advanced quantum technologies. What path could ET follow from its current quantum noise design towards the best sensitivity with future upgrades?
In this talk, I will give an overview of the current challenges related to quantum noise in ET, discuss the key parameters that influence it, and highlight several alternative configurations for both the near and long-term upgrades, and possible implications for the current design.
Speaker: Mikhail Korobko -
178
Einstein-Podolsky-Rosen quantum entanglement for broadband quantum noise reduction in future gravitational-wave detectors
Quantum Noise (QN) limits the sensitivity of ground-based Gravitational Wave (GW) interferometers (ITF) across all the frequency bandwidth (10Hz - 10kHz) 1. Current detectors are designed to achieve broadband QN Reduction (QNR) via frequency-dependent squeezing (FDS) generated in reflection of a 300 m long detuned filter cavity (FC) that is coupled with a frequency-independent squeezing (FIS) source [2, 3, 4]. However, the infrastructure required for the FC is extensive, and this issue is particularly critical for the future generation of GW detectors such as the Einstein Telescope (ET), where multiple km-long FCs are required 5.
Looking ahead to the post-O5 era and the third-generation detectors like ET, more compact, cheaper, and more flexible technologies for broadband QNR, without the need for external FCs, are desirable 5.
A very promising technique uses Einstein-Podolsky-Rosen (EPR) quantum entanglement 6. With this method, two entangled squeezed beams, the signal at the interferometer frequency, and the idler, detuned, are generated from the same source and then injected from the dark port of the ITF. Inside the ITF, the idler beam experiences squeezing ellipse rotation, effectively acting as a filter cavity. EPR squeezing can, in principle, replicate the function of FCs by creating entangled beams whose correlations can be used to reconstruct the desired FDS angle, thus eliminating the need for large, external FCs 6. Hence, this method allows broadband QNR within a considerably more compact setup. To explore the potential of this method, we are developing an experiment in Virgo's R&D squeezing laboratories to measure the effect of EPR-FDS in the audio band region of interest for terrestrial GW detectors 7. This experiment involves 20 members from several Italian universities and related INFN groups (Roma1, Napoli, Perugia, Genova), and South Korean institutions like KASI, Kyung Hee University, and Yonsei University. This talk will overview the current status of the EPR project and highlight its future potential.References:
[1] Phys. Scr. 96, 124054 (2021)
[2] Phys. Scr. 96, 104014 (2021)
[3] Phys. Rev. Lett. 131, 041403 (2023)
[4] Phys. Rev. Lett. 124, 171102 (2020)
[5] M. Korobko, Galaxies 13(1) 11 (2025)
[6] Nature Phys 13, 776–780 (2017)
[7] NIM.A, 1070,170008 (2025)Speaker: Francesco De Marco (La Sapienza University of Rome and INFN Roma1)
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Observational Science (OSB) Rooms 215 & 216
Rooms 215 & 216
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179
The synergy of Euclid and Einstein Telescope: cosmology with gravitational waves
Euclid is an ESA space mission launched in July 2023, designed to produce an all-sky map of galaxies with unprecedented precision. The mission will survey 14,500 square degrees with its Wide Survey, providing photometric redshifts for galaxies in the range $0
While the primary goal of the mission is to leverage galaxy clustering and weak lensing as cosmological probes to constrain the Universe’s dark energy components and expansion history, its catalogs will also have immense legacy value for gravitational wave multimessenger studies.
To explore this potential, the Euclid Consortium has recently established a new Science Working Group on Gravitational Waves. Several studies are currently investigating the synergy between Euclid data and present and future GW observations, including LVK O4-O5 runs and the Einstein Telescope (ET).
In March 2025, Euclid released its first public catalog, Q1, covering 63 square degrees. Future data releases will progressively expand the galaxy catalogs, providing critical insights into the host galaxies of GW events detected by current and upcoming GW observatories, as well as the overall background galaxy distribution.
In this talk, we will discuss the Euclid mission and its synergy with GW observations, including ET.
Speaker: Andrea Cimatti -
180
The great synergy of ET with next-generation GRB observatories
The huge luminosity, the redshift distribution extending at least up to z~10 and the association with the explosive death of very massive stars make long GRBs extremely powerful probes for investigating the early Universe (pop-III stars, cosmic re-ionization, SFR and metallicity evolution up to the “cosmic dawn”) and measuring cosmological parameters. At the same time, as demonstrated by the GW170817 event, GRBs are a key electromagnetic counterpart of gravitational waves produced by NS-NS and NS-BH merging events. GRB space mission projects for the next decade aim at fully exploiting these unique potentialities of the GRB phenomenon, thus providing an ideal synergy with the very large astronomical facilities of the future (e.g., ELT, CTA, SKA, Athena) and, in particular, with the Einstein Telescope (ET). For instance, the THESEUS mission, under study by ESA as candidate M7 for a launch in 2037, by providing an unprecedented combination of X-/gamma-ray monitors, on-board IR telescope and spacecraft autonomous fast slewing capabilities, would be a wonderful machine for the detection, multi-wavelength characterization and redshift measurement of any kind of GRBs and many classes of X-ray transients. Thanks to these unprecedented capabilities and a perfectly matched timeline with ET, this mission would thus provide at least several tens, and likely more than one hundred, EM counterparts to GW detections, thus greatly enhancing the scientific return of ET for multi-messenger astrophysics and cosmology, as well as extreme and fundamental physics with GRBs.
Speaker: Dr Lorenzo Amati (INAF - OAS Bologna) -
181
ET-WST synergy for next-generation gravitational wave multi-messenger observations
The Einstein Telescope (ET) will enable an unprecedented number of binary neutron star system merger (BNS) detections, extending beyond the Local Universe and revolutionizing gravitational wave (GW) multi-messenger (MM) astrophysics. To fully exploit the great scientific potential of MM observations of such events, an observing strategy has to be prepared well in advance of ET operations.
A major challenge will be the large localization volumes of GW signals, within which faint optical-NIR electromagnetic (EM) counterparts must be identified among numerous contaminant sources. Spectroscopy will likely become the bottleneck of GW MM science, being the only definitive tool to identify and characterize EM counterparts.
I will present new results of the simulations I carried out within the Division 4 of the ET Observational Science Board and the Time Domain Working group of the Wide-field Spectroscopic Telescope (WST) science team to assess the impact of next generation Integral Field and Multi-Object Spectroscopy (IFS and MOS) on the detection, identification and characterisation of EM counterparts of ET BNS.
I will consider different observational strategies, addressing key challenges in EM follow-up observations of ET BNS detections, and emphasize how ET can drive the development of future facilities.Speaker: Sofia Bisero -
182
Vera Rubin Observatory and Einstein Telescope: kilonova observation strategies to optimize target-of-opportunity follow ups
Next-generation gravitational wave (GW) observatories such as the Einstein Telescope (ET) will observe large numbers of binary neutron star (BNS) mergers across cosmic history and allow us to obtain precise parameter estimates for the events observed at low redshifts. The Vera Rubin Observatory will be a powerful instrument in the discovery and follow-up of optical counterparts of BNS mergers in the era of ET. Follow-up of electromagnetic (EM) counterparts of BNS mergers provides a unique window into the population studies of kilonovae (KNe) and gamma ray-burst (GRB) central engines and their properties. For this it is important to optimize follow-up observation strategies for BNS merger triggers to search for optical counterparts. We investigate the two different proposed configurations of the Einstein Telescope (ET Delta-10 km and ET 2L-15 km) in networks with current and future GW detectors, in particular focusing on different follow-up strategies for BNS mergers with Rubin. We use 10-year populations of BNS mergers and compare the results from different choices of NS mass distributions and equations of state (EOS). I will be presenting the results and projections from our work on synergies between ET and Rubin.
Speaker: Nandini Hazra (NCBJ Warsaw) -
183
Binary Neutron Star Merger, Cosmic Rays, and Neutrinow
I will review the connection between binary neutron star mergers, cosmic rays, and ultra high energy neutrinos. I will discuss the possibility of a multimessenger joint detection of gravitational waves and neutrinos from such mergers.
Speaker: Prof. Tomasz Bulik -
184
Multi-messenger observations in the Einstein Telescope era: binary neutron star and black hole - neutron star mergers
The Einstein Telescope (ET) will extend the reach of gravitational wave (GW) astronomy for stellar-mass compact binaries to unprecedented distances, significantly enhancing opportunities for multi-messenger discovery. Building on the landmark observations of GW170817 and informed by our recent population modeling studies (Colombo et al. 2022, 2024), we investigate the prospects for detecting and characterizing electromagnetic (EM) counterparts to binary neutron star (BNS) and black hole–neutron star (BHNS) mergers with ET. Using a synthetic cosmological population of BNS and BHNS systems, we simulate GW signal-to-noise ratios, sky localization uncertainties, and multi-wavelength EM signatures—including kilonovae, short gamma-ray bursts prompt and afterglows spanning radio to very high-energy bands. We evaluate the multi-messenger yield of ET under various detector configurations, both standalone and within a global network, and quantify the impact of key astrophysical uncertainties, such as the neutron star equation of state and compact object mass distributions. This talk will present our latest projections for the ET era, outlining the transformative scientific potential and the strategic challenges facing multi-messenger astronomy in the next decade.
Speaker: Alberto Colombo (INAF - OAR) -
185
Model-independent constraints in the context of multi-messenger cosmology
Gravitational wave (GW) and multi-messenger (MM) astronomy provides new ways to gain insights into the Dark Energy (DE) phenomenology, through the distance-redshift relation, as well as into potential deviations from General Relativity (GR), via the distance duality relation. Both analyses involve the same astrophysical observables, making MM astronomy a powerful tool to explore simultaneously the nature of DE and gravity.
To this end, provided our current ability to localize $\gamma$-ray bursts (GRBs), we employ a catalog of 38 of these events supposedly originated from binary neutron star (BNS) mergers detected by the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory. We generate a mock dataset of MM events by means of a prior-informed Fisher matrix approach and forecast the sensitivity of the Einstein Telescope (ET) to constrain cosmological and modified gravity (MG) parameters.
We compare the performance of standard DE and MG parametrizations with a more flexible, model-independent method based on Gaussian Processes (GP). We examine synergies among next-generation GW interferometers and cosmological probes such as Cosmic Microwave Background (CMB), Type IA Supernovae (SnIA) and Baryon Acoustic Oscillation (BAO) data. We capitalize on their complementarity to break parameter degeneracies, showing that fewer than 40 GRB-GW events will provide unprecedented accuracy in constraining the DE phenomenology as well as potential departures from GR.
Speaker: Andrea Cozzumbo -
186
The combination of ET and WST for future generation standard sirens analysis
The Wide-field Spectroscopic Telescope (WST) is an innovative 12-meter-class facility that combines a large field of view (3 square degrees) with a high-multiplex (30,000) multi-object spectrograph operating in both medium- and high-resolution modes (MOS). Additionally, it features a giant panoramic integral field spectrograph (IFS) covering 3×3 square arcminutes.
WST will produce the next-generation galaxy spectroscopic catalog, reaching up to z∼1.5 with high completeness, while also enabling the exploration of the Universe up to z∼5 through quasars and Lyman Break Galaxies with unprecedented coverage.
Such a catalog would be not only ideal but also essential for future gravitational wave observations such as Einstein Telescope (ET), as it will provide the reference catalog to identify the host galaxies of compact binary mergers needed to enable precision cosmology.
In this talk, I will present an overview of WST and its synergy with ET, also discuss the efforts we are coordinating within the WST Cosmology Group to develop the best possible catalogs for the study of dark sirens and their implications for cosmology.
Speaker: Michele Moresco
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179
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Site Preparation & Characterization (SCB) Room 409 at INAF-OAS
Room 409 at INAF-OAS
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187
Terrestrial and airborne gravimetry in the Sardinia (Italy) candidate area for the Einstein Telescope (ET)
We present the results of a gravimetric study conducted in the Sos Enattos mining site (northeastern Sardinia), an area identified as the Italian site for the potential underground installation of the Einstein Telescope (ET), a third-generation gravitational wave detector.
Currently, the ET project is in its preparatory phase, with efforts focused on performing feasibility studies for selecting the optimal installation site. It must meet strict geological and environmental criteria, the most critical being minimal anthropogenic and seismic noise.
To contribute to this effort, we applied the gravimetric method through both airborne and ground-based surveys. For the airborne survey, we employed the iCorus strapdown gravity sensor by iMar, covering the region near the Lula municipality in the Nuoro province. This survey aimed to acquire high-spatial-resolution gravity data and map the area's subsurface geological features. Additionally, using a Scintrex CG-6 spring-type gravimeter, a ground-based gravimetric survey was conducted at the Sos Enattos mining site to provide reference data for the airborne measurements. Both terrestrial and aerial data were referred to the absolute value of the gravity acceleration measured in the Sos Enattos area with the Microg LaCoste FG5#238 absolute gravimeter. Additionally, high accurate Airborne Lidar Surveys and GNSS ground reference points were acquired for improving the topographic correction and precisely georeferencing the gravimetric dataset.
Our findings provide new insights into the geological characteristics and allow to refine the geoid model in the Sos Enattos area, contributing to the assessment of its suitability for hosting the ET infrastructure.Speaker: Filippo Greco (Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Catania) -
188
Integrated analysis of the electrical resistivity measurement at the EMR-site, insight from structural analysis, borehole logs and microgravimetry.
The de-risking of the geologic structures in the EMR is a crucial step in the preparation of the Einstein Telescope. Alongside active seismic and gravimetry, Deep Electric Resistivity Tomography surveys are a key instrument to identify and characterize large structures in the subsurface.
We present the geologic interpretation of a Deep ERT profile in Val Dieu, Belgium crossing the Booze Val-Dieu Block. The profile spreads over a length of 7.5 km and was interpreted using the knowledge from recent borehole logs, including correlating seismic velocities variations and resistivity variations, geologic cross-sections and microgravity measurements. To consolidate the interpretation, synthetic modelling was performed, testing different geologic hypotheses.
Furthermore, we show our latest results from a Deep ERT survey in Hombourg, Belgium close to the recent drill sites in Hombourg and Obsinnich. The survey included two perpendicular profiles, 4.5 and 6.1 km long, revealing insights on several faults. For the first interpretation previous conventional ERT profiles and a 3D Deep ERT survey were included.Speaker: Yannick Forth (ULiège) -
189
The impact of local noise recorded at the ET candidate sites on the signal to noise ratio of CBC gravitational wave signals for the ET triangle configuration
We present an evaluation of how site dependent noise can affect the signal to noise ratio (SNR) of compact binary coalescence (CBC) signals in the future 3rd generation gravitational wave (GW) detector Einstein Telescope (ET). The design of ET is currently pushing the scientific community to study its scientific potential with respect to known, and possibly unexpected, GW signals using its design sensitivity curves. However, local ambient noise may have an impact on the ET sensitivity at low frequency and therefore affect the SNR of CBC signals at low frequency. Therefore, we study the impact of ambient noise on the ET sensitivity curve at the two sites candidate to host ET - Sardinia, in Italy, and the Euregio Meuse-Rhine (EMR) at the Netherlands-Belgium border - and infer the impact on the ET sensitivity curve and how the SNR of CBC signals at low frequencies is affected. We find that Sardinia shows results which are on par, if not better, than the design case. On the other hand, ambient noise for the current EMR sensitivity curve in Terziet causes a higher degradation of the SNR performances.
Speaker: Matteo Di Giovanni (La Sapienza Università di Roma - INFN Roma) -
190
Evaluating deep Neural Networks for subtracting Newtonian noise in GW detectors.
Newtonian noise (NN), arising from local density fluctuations due to seismic activities will limit the sensitivity of next-generation gravitational wave detectors at low frequencies. This study explores deep learning models as non-linear algorithms to predict and cancel NN.
As a preliminary experiment prior to obtaining Einstein Telescope data, we utilise data from the Virgo detector, which has an array of 24 seismometers and a tiltmeter acting as a proxy for surface-wave induced NN. We train deep learning models, including Long Short-Term Memory (LSTM) networks, Transformers, and Convolutional Neural Networks (CNN). Their performance is compared against conventional Wiener filtering methods, known to be the optimal linear filter. Our preliminary results demonstrate strong potential for deep learning methods in frequency bands of interest, indicating that these techniques will be beneficial for the Einstein Telescope.Speaker: Sacha Peters -
191
3D subsurface modeling at Limburg using multimodal surface waves
Limburg, a region located in the cross-border area between The Netherlands, Belgium, and Germany is the Euregio-Meuse-Rhine candidate site for hosting the Einstein Telescope. Recent studies to investigate the site’s subsurface suitability for hosting Einstein Telescope has seen several boreholes being drilled and deployment of arrays of geophones on the surface. In this study we present a 3D subsurface model up to depths of 500 meters which was estimated by making use of vertical component of ambient seismic noise data on the surface. Continuous seismic noise recordings for a period of 3 weeks were used to perform seismic interferometry which yields the empirical Green’s function between station pairs. The phase of the estimated Green’s functions was further used to perform Rayleigh-wave tomography, thereby obtaining a 2D distribution of phase and group velocities in the frequency band 1.5 – 5.0 Hz. The estimated phase and group velocities for every tomographic grid were then converted to a depth-dependent S-wave velocity model. Besides the Rayleigh wave fundamental model, the first overtone is also used to increase the accuracy of the estimated velocity model. Results show a good match between the estimated 3D model and the boreholes located in the region of study. An accurate 3D velocity model is important for reliable estimation of Newtonian noise as well for deciding the suitability of the underground to host the vertices of the Einstein Telescope.
Speaker: Soumen Koley (University of Liege) -
192
Noise Modeling at EMR: planning the development of sophisticated models
Modeling seismic waves to Newtonian Noise is of critical importance to understand the impact on the instrument of residual noise at the vertices of ET. The models that currently exist are considered not sufficiently sophisticated to appropriately take into account the layered structural geology in the EMR region. Plans and deliverables are presented to develop the required models to resolve this issue and improve the estimates of Newtonian noise in this region.
Speaker: Stan Bentvelsen (Nikhef)
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187
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Coffee break
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Instrument Science (ISB) Plenary Room
Plenary Room
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193
Locked cavity scan - using heterodyne detection with a phase camera
Increasing the optical circulating power in gravitational-wave detectors is a straightforward way of increasing detection sensitivity. However, current detectors are limited in the amount of achievable circulating power far below the design values. Optical absorption in the test masses and main optics leads to thermal effects that shift the eigenmodes of the optical cavities and cause control issues such as parametric instabilities.
Here we present the experimental results of a technique using optical injection to perform a scan of the higher-order modes of a cavity and extract the modal weights. We use a phase camera in transmission to confirm the mode basis and image modes up to order 9. We showcase as well the capability of the phase camera to determine the optical phase between carrier and co-resonating higher-order modes, which can be used for optical suppression of parametric instabilities. Finally, we test the scheme’s capability of tracking the cavity g-factor while locked. This could find application in gravitational-wave detectors to track in real-time the thermal transient in the arm cavities due to the optical absorption.
Speaker: Ricardo Cabrita (UC Louvain) -
194
CAOS: Mechanical details and studies of the Vacuum Towers under construction.
The CAOS facility in Perugia serves as a specialized lab for testing mechanical and optical systems for the Einstein Telescope (ET). It will host a seismic-isolated Fabry-Perot cavity. The current research and development efforts include testing ET's full-sized Super Attenuators, creating integration tools and procedures for lateral-entry payload access at the base of the tower, and evaluating NEG pumps within Super Attenuator environments.
Two 15-meter-high stainless steel towers are currently being constructed. Extensive use of Finite Element (FE) techniques has refined the towers' mechanical design, addressing both static and dynamic loads. The designs have been optimized based on Von Mises stress analyses and mechanical resonance frequencies. This presentation will detail the mechanical solutions adopted for the towers and the Finite Element analysis methods used during the design phase.Speaker: Gabriele Capoccia (INFN-PG) -
195
Low energy electrons for frost and electrostatic charging mitigation in future gravitational wave detectors: a status report
In the upcoming third generation of gravitational wave (GW) detectors, the unavoidable build-up of a frost layer on cryogenically cooled mirrors and their electrostatic charging may represent two potentially critical showstoppers for GW detection. We already proposed a possible mitigation solution for both such issues, relying on irradiation with low energy electrons (from 20 to few hundreds eV) of the optical elements. Low energy electrons are known to interact only with the very top layers (some nm) of any irradiated surface, are known to be very efficient in inducing gas desorption and, by properly tuning their energy, they can neutralize both positive and negative charges on surfaces. Therefore, low energy irradiation of mirrors’ surfaces seems ideal to induce frost desorption and neutralize charge without damaging the mirror surfaces’ optical properties.
Here we present the status of the experimental activity carried out at LNF-INFN and the necessary R&D activity aiming to pass from a valid and demonstrated concept to the possible integration of the method in the complex low frequency tower design.Speaker: Luisa Spallino -
196
First Cooling of the Refrigeration Line Designed for the Cryogenic Payload in the ARC Laboratory
The Amaldi Research Center (ARC), located at Sapienza University of Rome, will host the first experiment of a cooling system designed for a full-scale cryogenic payload. Following the solid conduction cooling approach, two refrigeration lines, each driven by two Pulse Tube cryocoolers, will be used to cool down a cryogenic payload housed in a specially designed 3-meter-tall cryostat.
The laboratory was inaugurated on April 4th, and following this, the first refrigeration line, equipped with a test chamber, was successfully cooled down. The vibrations from the Pulse Tube cryocoolers have been effectively damped using soft heat links to connect suspended components within the refrigeration line. The vibration contribution was measured using cryogenic sensors and interferometry-based sensing along the line.
The payload has been successfully assembled and it is currently in the black coating phase, with completion expected by the end of 2025. The cryostat, featuring the Rigid Multi-Layer solution, is scheduled for delivery in late 2025.
Speaker: Marco Ricci -
197
Measuring the Volatile Residue of Hydrocarbons in ET: the CRDS UHV System at the CIRCE Laboratories
A significant challenging feature of the ET vacuum system is the requirement on the hydrocarbon partial pressure ($p_{hy}$) for molecules heavier than 100 atomic mass unit (amu), as explained in the ET design report
\begin{equation}
p_{hy}\le1\cdot10^{-14}\,mbar
\end{equation}
In order to reach such an ambitious result, both the non volatile and volatile residue of hydrocarbons should be taken into account. In particular, the latter can introduce a non negligible contribution to the partial pressure in the vacuum system.
Nowadays, it is quite complex to provide an accurate measurement of the hydrocarbon partial pressure in Ultra High Vacuum (UHV) conditions. The typical approach involves a Residual Gas Analyzer (RGA), for which it is not simple to distinguish the contribution of different molecules in the spectrum provided by this instrument. Indeed, the RGA analysis requires a deep knowledge of the typical cracking fragments of the molecules that complicates the identification of many partial pressures in a vacuum system.
This work reports on the status of the new facility in UHV at the CIRCE laboratories $[1]$, that has been designed to perform accurate measurements of $p_{hy}$ using the extremely high-sensitivity technique known as Cavity Ring-Down Spectroscopy (CRDS) $[2]$.
The technique is based on the measurement of the decay time of the transmitted intensity, once the incident radiation is instantaneously switched off. Such a time constant (known as cavity ring-down time) allows to determine the intracavity absorption coefficient, from which the absorbing gas concentration and partial pressure can be retrieved $[2]$.
The system marks the first application of CRDS in UHV conditions, aiming to perform direct and accurate measurements of the distinctive cracking fragments of ultra light hydrocarbons ($<$ 100 amu) in order to remove the mass degeneracy in the RGA analysis of heavier hydrocarbons.
The present work aims to promote the CRDS in UHV, which is rather promising in measuring $p_{hy}$ at the stringent levels required for ET, especially in the perspective to use it in the chain of processes for the UHV cleaning test, complementing the established Fourier-Transform Infrared spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) techniques.$[1]$ E. Tofani, S. Gravina, V. D’Agostino, E. Fasci, A. Grado, and L. Gianfrani, “Volatile Residue of hydrocarbons in ET: a UHV chamber for CRDS at the CIRCE laboratories", ET Docs ET-0163A-24 (2024)
$[2]$ L. Gianfrani, S.-M. Hu, W. Ubachs,“Advances in cavity-enhanced methods for high precision molecular spectroscopy and test of fundamental physics.", La Rivista del Nuovo Cimento 47, 229–298 (2024)
Speakers: Prof. Aniello Grado (Dipartimento di Fisica e Geologia, Università degli Studi di Perugia, Perugia, Italia; INFN-Sezione di Perugia), Emanuele Tofani (Università degli studi della Campania "Luigi Vanvitelli"-INFN Napoli), Dr Stefania Gravina (Dipartimento di Matematica e Fisica, Università degli studi della Campania “Luigi Vanvitelli", Caserta, Italia; INFN-Sezione di Napoli) -
198
Cryogenic Instrument Science Development
The Glasgow Cryogenic Interferometer Facility (GCIF) is one of the prototype facilities working in the ET Collaboration to develop technology, demonstrate integration and prove the concepts and validate the technology readiness of critical elements for the cryogenic Einstein Telescope LF detector.
We report here on the progress of the instrument science program of the GCIF, including the suspended payload design, crystalline material science, laser stabilisation, interferometer control scheme and optical layout for this prototype experiment and report to the ET Collaboration on research and development progress.Speaker: Andrew Spencer
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193
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Observational Science (OSB) Rooms 215 & 216
Rooms 215 & 216
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199
Post-Newtonian and Numerical Waveform Hybridization: Compatibility and Development
In this presentation, I will introduce one of our group's ongoing projects, which aims to utilize the post-Newtonian approach implemented in CBwaves for waveform hybridization. In the initial phase, we will assess the compatibility of CBwaves with available numerical waveforms from the SXS collaboration before progressing toward the development of a hybrid model. I will provide an overview of CBwaves, along with the planned modifications and improvements necessary for this project.
Speaker: Balázs Kacskovics -
200
Modeling matter(s) in SEOBNRv5THM: Generating fast and accurate effective-one-body waveforms for spin-aligned binary neutron stars
We present SEOBNRv5THM, an accurate and fast gravitational-waveform model for quasi-circular, spinning, non-precessing binary neutron stars (BNS) within the effective-one-body (EOB) formalism. It builds on the binary-black-hole approximant SEOBNRv5HM and, compared to its predecessor SEOBNRv4T, it i) incorporates recent high-order post-Newtonian results in the inspiral, including higher-order adiabatic tidal contributions, spin-induced multipoles and dynamical tides for spin-aligned neutron stars, ii) includes the gravitational modes $(\ell, |m|)=(2,2),(3,3),(2,1),(4,4),(5,5),(3,2),$ and $(4,3)$, iii) has a time of merger calibrated to BNS numerical-relativity (NR) simulations, iv) accurately models the pre-merger $(2,2)$ mode through a novel phenomenological ansatz, and v) is 100 to 1000 times faster than its predecessor model for BNS systems with total mass $M \geq 2\, M_\odot$. Thus, SEOBNRv5THM can be used in Bayesian parameter estimation, which we perform for two BNS events observed by the LIGO-Virgo Collaboration, GW170817 and GW190425. The model accurately reproduces BAM and SACRA NR waveforms with errors comparable to or lower than the intrinsic NR uncertainty. We validate the model against the other state-of-the-art BNS waveform models NRTidalv3 and TEOBResumS and find differences only for highly spinning and highly tidally deformable BNS, where there is no NR coverage and the models employ different spin prescriptions. Our model serves as a foundation for the development of subsequent SEOBNR waveform models with matter that incorporate further effects, such as spin-precession and eccentricity, to be employed for upcoming observing runs of the LIGO-Virgo-KAGRA Collaboration and future facilities like the Einstein Telescope.
Speaker: Marcus Haberland (Max Planck Institute for Gravitational Physics (Albert Einstein Institute)) -
201
Tidal heating as probe of black hole horizon
With the observation of the multiple binary inspirals, we begin to question whether the components of the binary are black holes or some exotic compact objects (ECOs). The "black holeness" or the deviation from it can be tested in several ways. The distinguishing feature of a black hole from ECOs in the presence of the horizon. This surface acts as a one-way membrane that absorbs energy. Due to this different behavior from ECOs, in the last stages of an inspiral black hole exchange energy. These backreact on the orbit, transferring energy and angular momentum from their spin into the orbit. This effect is called tidal heating. I will discuss how tidal heating can be used to test "black hole ness"; and distinguish black holes from other compact objects. I will also discuss how the black hole tidal heating affects waveform modeling.
Speaker: Sayak Datta (GSSI) -
202
Probing the maximum temperature ever reached in the universe with ET
There are a few examples where the accuracy of theoretical predictions is running ahead of that of experiments. One is the case of gravitational waves naturally sourced by hydrodynamical fluctuations in a thermal medium. These signals are motivated by the Standard Model of particle physics, predicting that, for the first three hundred thousand years, the fundamental constituents of the matter filling our universe were in equilibrium with each other, constituting a thermal plasma. This picture is confirmed by the fact that we observe a perfect black-body electromagnetic background radiation in each direction of the sky, the CMB. Since the corresponding gravitational wave spectrum is expected to show rapid growth at high frequencies, ET may offer unprecedented prospects to detect these signals. Nevertheless, while the spectral shape is well understood, the maximal amplitude is set by the plasma temperature at emission. To set an upper bound on the gravitational wave production, we have evaluated the maximal temperature reached in different early universe scenarios.
Speaker: Simona Procacci (U. Geneva) -
203
Continuous wave search with Einstein Telescope: impact of an astrophysical background from coalescing binaries.
The search for continuous gravitational waves (CWs) with the third-generation detector Einstein Telescope (ET) will face new challenges due to the increased presence of coalescing binary signals. Indeed, thanks to the improved sensitivity, ET will detect O(1e5) compact object coalescences per year. Moreover, its extended frequency range, reaching down to nearly 5 Hz, will allow the detection of a significant portion of the inspiral phase of the binaries before they merge. As a result, overlapping inspiral signals will form an astrophysical background that could impact CW searches.
To investigate this effect, we simulate the spectrum of coalescence signals in the [2-256] Hz range, where their contribution is expected to be most significant. We perform CW signal injection studies in the ET framework using the Frequency Hough pipeline, currently used in the LIGO-Virgo-KAGRA CW searches, with and without the simulated coalescence background in the ET instrumental noise. By analyzing the differences in CW detection efficiency between these cases, we aim to quantify the impact of this background on CW searches and explore possible mitigation strategies for future analyses.Speaker: Elena Codazzo -
204
Low frequencies, long observing runs and young unknown neutron stars: challenges for future continuous gravitational wave searches.
Wide-band searches for continuous gravitational waves are essential to reveal unknown neutron stars that may be close enough to us to be detectable. Currently, analyses performed on data from 2G detectors for unknown sources cover all possible sky directions, but are restricted in the rotational parameters by their computational cost and by the limited bandwidth of the detectors at low frequencies. The simplest possible model describes neutron stars slowing down at a constant rate by a first-order spin-down parameter that, for one-year long observing runs, is expected by neutron stars that are about thousands of years old, or even older. However, with ET the perspective of several-years long observing runs suggests to enlarge the parameter space to search for signals with an higher-order spin-down. This enlargement, together with the expected widening of the detector bandwidth down to few-Hertz frequencies, will allow to search for younger neutron stars, up to hundreds or even tens of years old. In this talk, I will present the opportunities opened by 3G detectors to neutron-star science, together with the practical complications connected.
Speaker: Lorenzo Pierini (Istituto Nazionale di Fisica Nucleare) -
205
Core-Collapse detection rates from Einstein Telescope
Gravitational waves offer a promising opportunity to investigate the explosion mechanism behind the Core-Collapse Supernovae, as they are expected to originate from the oscillations of the proto-neutron star formed during the collapse. The third-generation detector Einstein Telescope (ET), with its sensitivity to low-frequency signals, could detect GW signatures from Core-Collapse Supernovae.
In this talk, I will present our preliminary estimate of Core-Collapse Supernova detection rates (CCSNR) for the ET within the Milky Way and the Magellanic Clouds. Our estimates are based on observational data and massive star distributions modeled with TRILEGAL. Additionally, by utilizing simulated gravitational waveforms from CCSNe and the GWFISH simulation software, we analyzed SNR-weighted density maps and determined the detection horizon for these signals.
Speaker: Ines Giudice -
206
Core-Collapse Supernovae: Future Synergy Between LSST and ET
The Vera Rubin Observatory’s (VRO) Legacy Survey of Space and Time (LSST) will revolutionize time-domain optical astronomy, detecting faint sources down to r~27.5 mag and generating nearly 32 trillion observations over 10 years. Among these, ~10 million will be supernovae (SNe), covering a wide range of redshifts and enabling studies of known and rare types, progenitors, and strongly lensed SNe (LSST Collaboration, Abell, P. A., Allison, J., et al. 2009).
Multimessenger astronomy is a key LSST objective. The detection of neutrinos from SN 1987A highlighted the potential of observing CCSNe through multiple messengers, and models predict gravitational wave (GW) emission from these events. A synergy between LSST and the Einstein Telescope offers a unique opportunity to detect the first GW signal from a CCSN.
We focus on LSST’s ability to characterize CCSNe using a dataset of 6730 high-detail simulations from Moriya et al. 2023, analyzed with CASTOR (Simongini et al. 2024) to reconstruct the parametric map. We put particular emphasis on the synergy with current and future multiwavelength and multimessenger detectors. Comparing reconstructed and injected parameters, we find LSST alone cannot fully constrain progenitor properties and explosion parameters due to limited spectral coverage, bolometric luminosity uncertainties, and redshift-absorption degeneracy. Follow-up observations, particularly in the infrared, will be essential for precise parameter determination. Additionally, LSST’s rigorous survey schedule limits targeted follow-ups.
This work is under review at A&A.
Speakers: Andrea Simongini (INAF - Osservatorio Astronomico di Roma), Fabio Ragosta, Silvia Piranomonte
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199
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Site Preparation & Characterization (SCB) Room 409 at INAF-OAS
Room 409 at INAF-OAS
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207
Analysis of seismic ambient noise at the Lausitz ET candidate site
The Lausitz is the third potential site to host the Einstein Telescope (ET). Site characterization is in progress since late 2023 based on the ongoing survey for a planned underground laboratory „Low Seismic Lab“ (LSL). The LSL will be a central part of the Deutsche Zentrum für Astrophysik (DZA, German Center for Astrophysics) which is currently being established. Site requirements for the LSL follow ET guidelines and include measurement and identification of ambient noise sources and geophysical, geological, and hydrological 3D characterization of the future site. The surveyed region covers an area large enough to host both geometry options (triangle- or L-configuration), entirely located within the mostly undisturbed Lausitzer Granodiorite Massif.
In this talk, I focus on the ambient seismic noise study, including surface arrays and borehole recordings. I will discuss the results of past and ongoing deployments, and future campaigns to extend the area.
Speaker: Dr Mike Lindner (DESY - DZA) -
208
Noise discussion and general SCB issues
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207
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Lunch
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Lunch meeting: EB
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Communications Room 213
Room 213
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209
WelcomeSpeakers: Prof. Dorota Rosinska (University of Warsaw), Dr Vincenzo Napolano (EGO Communication Responsible)
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210
ET Italy communication activities: last updates
The communication of Italy's candidacy to host the Einstein Telescope is gaining momentum through multiple channels: institutional communication (website and social media), events at international, national, and regional levels — especially in the candidate area — and media engagement.
In this talk, we will present the latest updates on ongoing initiatives.Speaker: Matteo Serra - 211
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212
DZA Strategies on Communication and OutreachSpeaker: Dr Mike Linder
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213
One year of the Einstein Telescope Education Centre
In the Summer of 2024, the Discovery Museum in Kerkrade and Maastricht University started the Einstein Telescope Education Centre (ETEC), a four-storey exhibition and learning facility for gravitational waves and its instrumentation, intended for upper classes of secondary education in the EMR-region. In one year of operation, ETEC has hosted many school classes, giving them a day-programme on the science of Einstein Telescope, relating it to what they already know from their high school physics classes. In this talk, I will give an overview of ETEC's programme, the experiences obtained, and the plans for its future exploitation for education of Einstein Telescope.
Speaker: Gideon Koekoek (Maastricht University) -
214
ETIC Lab Journey - Your Digital Guide to ET's Innovation Labs in Italy
ETIC Lab Journey is an interactive web app designed to explore the laboratories of the ETIC (Einstein Telescope Infrastructure Consortium) project, an initiative by the Italian Ministry of University and Research, led by the National Institute for Nuclear Physics (INFN). Launched in 2023, the project has two main objectives: conducting a feasibility and site characterization study in Sos Enattos, and developing a national network of laboratories within INFN, universities, and research institutions involved in ET. These labs focus on enabling technologies for the future Einstein Telescope, including seismic filtering systems, low-frequency suspension control for optics, low-noise cryogenic systems to reduce thermal noise, and innovations in photonics, optics, electronics, and mirror materials. Powered by Google Earth, the app provides an overview of the lab network and promotes public engagement through dedicated multimedia resources.
Speaker: Giuseppe Greco -
215
The Unreasonable Effectiveness of Analogy in the Natural Sciences and Their Public Dissemination: The Case of Gravitational Waves
The title of this paper, a clear paraphrase of Eugene Wigner’s renowned essay on the role of mathematics in the natural sciences, is intended to highlight the epistemological significance of analogical reasoning—a process that the history of science has shown to be pivotal across numerous domains and in a wide range of discoveries. The resemblance between concepts, the referencing and evocation of pre-existing ideas through aesthetically resonant metaphors, allows these ideas to be set in motion, to move beyond axioms and empirical evidence, and to venture—boldly—into directions that would otherwise remain inaccessible. The use of analogy is often explicitly acknowledged in the works of great scientists; a notable example is Albert Einstein, who makes deliberate use of it—for instance, when introducing his concept of gravitational waves by stating that the relevant calculation is carried out “in a manner analogous to that of retarded potentials in electrodynamics.” The aim of this contribution is therefore to initiate an analysis of the role of analogical reasoning in the particularly evocative case of the term “wave”, and to illustrate how I employ this strategy within Chirp!, a page which I intend to develop as a platform for the public dissemination of the GraWita project and with a specific focus on the forthcoming research to be conducted using the Einstein Telescope.
Speaker: Angelo Adamo (INAF/IASF Palermo) -
216
Using Digital Storytelling to Bring Gravitational Waves to School: the GRAVIS Project
Primary and lower secondary school students are naturally curious, often exhibiting a "little scientist" attitude. However, curiosity alone is not enough for developing structured scientific thinking, essential for their education. We present the GRAVIS project, an educational program which brings together gravitational waves physics and digital storytelling to engage students in inquiry-based learning, hands-on activities, and narrative creation. Developed in collaboration with Einstein Telescope Italy, it fosters critical thinking, creativity, and reflection on scientific discovery. By incorporating AI tools and real-world connections, GRAVIS aims to deepen engagement and prepare students for future STEAM education and careers
Speaker: Matteo Tuveri (Università di Cagliari e INFN Cagliari) -
217
Upcoming activities at the GR24/Amaldi16 conference
The joint GR24 and Amaldi16 meeting will be held in Scotland, July 2025 and we are excited to share the public outreach and engagement program with the ET community. At the GR/Amaldi conference there will be two public lectures from Erin MacDonald and Carole Mundell. At the public lecture we will be running an exhibition showcase of outreach demonstrations and invite all participants to share their demonstrations and activities in addition to a Science-Art gallery. We are also running a Wikipedia Edit-a-thon event to improve scientific literacy around GR and GW and boost the biography profiles for under-represented people in our field. Finally, we are very excited by the new collaboration with the Science Ceilidh group to create public dances inspired by GW science, these dances will be debuted at the conference dinner as the starting point of an anticipated program of social engagement using dance to communicate GW science.
Speaker: Andrew Spencer
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209
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Instrument Science (ISB) Plenary Room
Plenary Room
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Observational Science (OSB) Rooms 215 & 216
Rooms 215 & 216
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218
Spectral density of astrophysical stochastic backgrounds
I will discuss a recent first-principle derivation of the spectral features of astrophysical stochastic backgrounds produced by populations of compact binary coalescences (CBCs). The treatment is based on the observation that, among the parameters characterizing a CBC, some of them (extrinsic) are distributed uniformly following symmetry principles, while other (intrinsic) carry the more complicated dependence on the astrophysical scenario. Averaging over the extrinsic parameters allows the extraction of simple structures in the spectral density, ultimately leading to an unpolarized background (which is also isotropic if the underlying distribution of sources is isotropic). Shot noise effects, due to the specific realization of a finite number of events, produce anisotropies and give non-vanishing Stokes parameters for both circular and linear polarizations. It is noticeable that the Stokes parameters for linear polarizations do not vanish even in the isotropic case. This fact, which can be justified in full generality, has been previously overlooked in the literature. Numerical results for populations of CBCs will be showed. Throughout the talk, deviations from stationarity due to the finite observation time will also be described. The talk is based on 2411.04028.
Speaker: Dr Enis Belgacem (Université de Genève) -
219
Characterizing the detectability of cosmological backgrounds at third-generation detectors
The subtraction of the astrophysical foreground to reveal an underlying cosmological stochastic background poses a significant challenge for third-generation detectors. We present a novel approach for characterizing the confusion noise originating from the superposition of undetected astrophysical sources and the residuals from the subtraction of resolved signals, where we average the cross-correlated partially cleaned detectors’ outputs over many noise realizations. Crucially, we stress that the masking effect of the astrophysical foreground depends on the specific cosmological search conducted through the employed filter function. We show that, in a network comprising Einstein Telescope and two Cosmic Explorers, black hole binaries do not compromise the sensitivity to cosmological searches; while the effect of neutron star binaries, albeit substantial, is less pronounced compared to what was obtained with more heuristic methods.
Speaker: Niccolò Muttoni -
220
Tainted Love: Systematic biases from ignoring environmental tidal effects in gravitational wave observations
Binary black hole systems are typically assumed to evolve in vacuum. However, the environment surrounding the binary components can influence their properties, such as their tidal deformability, affecting the gravitational waveform produced by the binary and its interpretation in gravitational wave data analysis.
In this talk, focusing on next-generation experiments, such as the Einstein Telescope and LISA, we quantify the systematic biases in gravitational wave observations that arise when tidally deformed binaries are interpreted as occurring in vacuum. We consider binaries over a range of masses and compare different phenomenological models for the dynamical evolution of the tidal deformability. We find that systematic biases could significantly affect the measurability of the binary parameters if tidal effects are not carefully modeled.
Speaker: Dr Francesco Iacovelli (Johns Hopkins University) -
221
Characterizing, Not Just Detecting: Bayesian Neural Networks for Gravitational-Wave Physics
Gravitational waves provide a powerful means to perform null tests of strong-gravity physics. Statistical methods based on hierarchical inference, adapted from population studies, have been developed to confidently identify potential signatures of new physics. While these methods are well-suited for detection, they provide limited insight into how exotic physics depends on standard degrees of freedom, such as the mass and spin of an observed black hole. In this talk, we present an extension of hierarchical tests that enables the modeling of such dependencies in a flexible and theory-agnostic manner using fully connected neural networks. Additionally, we incorporate Bayesian neural networks and variational inference to model epistemic uncertainty in the network weights, optimizing the hierarchical population likelihood. Finally, we also discuss an alternative optimization strategy based on Gaussian Process Regression.
Speaker: Costantino Pacilio -
222
The impact of local noise recorded at the ET candidate sites on the signal to noise ratio of CBC gravitational wave signals for the ET triangle configuration
We present an evaluation of how site dependent noise can affect the signal to noise ratio (SNR) of compact binary coalescence (CBC) signals in the future 3rd generation gravitational wave (GW) detector Einstein Telescope (ET). The design of ET is currently pushing the scientific community to study its scientific potential with respect to known, and possibly unexpected, GW signals using its design sensitivity curves. However, local ambient noise may have an impact on the ET sensitivity at low frequency and therefore affect the SNR of CBC signals at low frequency. Therefore, we study the impact of ambient noise on the ET sensitivity curve at the two sites candidate to host ET - Sardinia, in Italy, and the Euregio Meuse-Rhine (EMR) at the Netherlands-Belgium border - and infer the impact on the ET sensitivity curve and how the SNR of CBC signals at low frequencies is affected. We find that Sardinia shows results which are on par, if not better, than the design case. On the other hand, ambient noise for the current EMR sensitivity curve in Terziet causes a higher degradation of the SNR performances.
Speakers: Davide Rozza (University of Milano-Bicocca & INFN-MIB), Matteo Di Giovanni (La Sapienza Università di Roma - INFN Roma) -
223
Challenges in stochastic background searches in the first ET MDC
This talk will present the analysis of the first ET MDC using the pygwb pipeline to search for an isotropic stochastic background. We compare the measurement to the theoretical prediction derived from the list of sources and quantify the differences, providing valuable insights into stochastic searches in the presence of high signal-to-noise ratio signals. Additionally, we will discuss the information obtained about the population of compact binary coalescences over cosmic time from the measurement of the stochastic background. Moreover, we will consider consequences for the search for underlying cosmological backgrounds.
Speaker: Michael Ebersold (University of Zurich) -
224
The null stream of the Einstein Telescope in its triangular configuration
Several uses of the null stream have been proposed, which indicate a fundamental advantage provided by the null stream for the detection and analysis of GW signals. In my talk, I will review and scrutinize the arguments, and I will conclude that we do not have a convincing argument yet that the ET null stream indeed offers a fundamental benefit to GW data analysis.
Speaker: Jan Harms
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218
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Coffee break
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Communications Room 213
Room 213
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225
MaGIC: introducing an international teacher’s programme on Einstein Telescope
Gravitational wave science, and instrumentation in particular, has a surprisingly strong connection to the typical secondary curriculum in secondary education. As such, Einstein Telescope offers great opportunities for teachers and students, and is ideally suited to show students that they too can understand the newest discoveries, practice the physics of their high school curricula in an exciting setting, and to play an active role in it. To prepare, the MaGIC programme offers a yearly in-person Summer School to provide them with a solid theoretical background and the educational methods to bring Einstein Telescope in the classroom.
In this talk, I will lay out the MaGIC programme, explain its didactics and curriculum, and how it is intended to create a Europe-wide teacher community on the physics and instrumentation of Einstein Telescope.Speaker: Gideon Koekoek (University of Maastricht) -
226
Discussion:Towards an Early Career Mentorship and Training Programme for the Einstein Telescope Collaboration
The Einstein Telescope (ET) Preparatory Phase project is a Horizon Europe-funded infrastructure project that aims to support critical activities of the ET community in the preparatory phase of the experiment, including technical design, costing and site selection for the observatory and identification of ET’s scientific, socio-economic and environmental impact. Work Package (WP) 10 of ET-PP concerns “Education, Outreach and Citizen Engagement” and has the mandate to promote to the widest possible audience the enormous scientifical potential of ET.
A key deliverable of WP10 is to develop a plan for an Early-Career Scientist Mentorship and Training programme for the ET Collaboration. In this contribution I will provide an overview of the work being carried out towards this deliverable. I will first review the many examples of good practice that exist in related mentorship and training programmes within the gravitational-wave community and beyond. We will then facilitate an open dialogue with early-career scientists attending the Einstein Telescope Collaboration; this will tease out and reflect upon early-career colleagues’ mentorship and training needs – particularly those which are distinct or bespoke compared with those of other gravitational-wave projects. This dialogue will help to shape the WP10 deliverable outcome report which will be submitted to the EU in autumn 2025.
Speakers: Martin Hendry (University of Glasgow), Marek Biesiada (NCBJ), Prof. Dorota Rosinska (University of Warsaw), Gideon Koekoek, Sascha Rieger (LVK/LISA/ET) -
227
Discussion: Building the ET community via social media
In this session, we’ll dive into the Einstein Telescope’s supranational social media activities. Over the past months, we’ve accelerated our efforts - launching new profiles, broadening our reach, and sharing a diverse range of content. Together, we’ll examine real examples and brainstorm ways to elevate our strategy. We’ll use the “Rose–Bud–Thorn” exercise to highlight successes, identify areas for improvement, and discover challenges that we need to tackle.
Speakers: Yuliya Hoika (University of Warsaw), Dr Vincenzo Napolano (EGO Communication Responsible) -
228
Creative Workshop: Producing high-impact visual resources for ET
We will develop first ideas for interesting & informative visual outreach materials, exploring the science, technology, international team & social impact of the Einstein Telescope. We are looking for input from ET members across the project, working in different areas and roles.
Speakers: Sascha Rieger (LVK/LISA/ET), Dr Livia Conti (INFN), Dr Isabel Cordero
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225
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Instrument Science (ISB) Plenary Room
Plenary Room
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Observational Science (OSB) Rooms 215 & 216
Rooms 215 & 216
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229
Null Stream Based Glitch Mitigation for Gravitational Wave Parameter Estimation
Gravitational wave (GW) detectors routinely encounter transient noise bursts, known as glitches, which are caused by either instrumental or environmental factors. Due to their high occurrence rate, glitches can overlap with GW signals, as in the notable case of GW170817, the first detection of a binary neutron star merger. Accurate reconstruction and subtraction of these glitches is a challenging problem that must be addressed to ensure that scientific conclusions drawn from the data are reliable. This problem will exacerbate with third-generation detectors like Einstein Telescope (ET) due to their higher detection rates of GWs and the longer duration of signals within the sensitivity band of the detectors. Robust glitch mitigation algorithms are, therefore, crucial for maximizing the scientific output of next-generation GW detectors. For the first time, we demonstrate how the null stream inherent in ET's unique triangular configuration can be leveraged by state-of-the-art glitch mitigation methodology to essentially undo the effect of glitches for the purpose of estimating the parameters of the source. The null stream based approach enables mitigation and subtraction of glitches that occur arbitrarily close to the peak of the signal without any significant effect on the quality of parameter measurements, and achieves an order of magnitude computational speed-up compared to when the null stream is not available. By contrast, without the null stream, significant biases can occur in the glitch reconstruction, which deteriorate the quality of subsequent measurements of the source parameters. This demonstrates a clear edge which the null stream can offer for precision GW science in the ET era.
Speaker: Harsh Narola -
230
DeepExtractor: Time-domain reconstruction of signals and glitches in gravitational wave data with deep learning
Gravitational wave (GW) interferometers detect faint signals from distant astrophysical events but are also highly susceptible to background noise. Among these noise sources are transient glitches, which can mimic or obscure astrophysical signals. The next-generation Einstein Telescope (ET) will offer unprecedented sensitivity that will yield significantly higher detection rates and enable the detection of longer duration signals. With approximately 1 in 4 events being impacted by glitches in current generation detectors, the increased sensitivity of ET will amplify glitch-related challenges, making fast and robust glitch reconstruction and mitigation strategies essential. This research presents DeepExtractor, a deep learning framework designed to reconstruct signals and glitches with power exceeding background noise. DeepExtractor operates by predicting and subtracting the noise component of the data, providing an accurate reconstruction of the underlying signal or glitch. Our model achieves a 0.9% median mismatch in simulated glitch reconstruction, outperforming several deep learning baselines. It also surpasses BayesWave in glitch recovery while providing a dramatic computational speedup—processing a glitch in 0.1 seconds on a CPU, compared to BayesWave’s approximately one-hour runtime per glitch. Additionally, we validate DeepExtractor’s effectiveness on real LIGO data using the Gravity Spy dataset. Beyond current detectors, DeepExtractor is already applicable to the null stream in ET’s triangular configuration, enabling glitch removal to improve source parameter estimation. We also outline its potential for glitch mitigation in ET’s 2-L configuration, where it learns to preserve signals that are coherent between detectors while removing incoherent glitches.
Speaker: Tom Dooney -
231
PINNGraPE: Physics-Informed Neural Network for Gravitational-wave Parameter Estimation with unmodeled search algorithms
Unmodeled data analysis techniques in the LVK collaboration, particularly coherent Wave Burst (cWB), do not assume any physical constraints when detecting GW events. While this allows for the detection of unmodeled signals with great efficiency, it limits the ability to accurately estimate source properties in the case of CBCs. Physics-Informed Neural Networks (PINNs) offer a promising solution to this challenge, both for LVK and ET unmodeled pipelines: a physics-informed neural network can perform PE while incorporating physical constraints directly into the loss function. This talk will explore how PINNs can address source PE within unmodeled pipelines and will present the latest promising results from the PINNGraPE algorithm.
Speaker: Matteo Scialpi (INFN - University of Ferrara) -
232
A weakly-modeled search for compact binary coalescences in the Einstein Telescope
With a sensitivity ~10 times that of current-generation gravitational wave (GW) detectors, the Einstein Telescope (ET) should be able to observe thousands of compact binary coalescence (CBC) signals per day, up to a redshift z=20. However, the high rate of signals calls into question whether existing data-analysis methods are directly applicable to ET data. Mock data challenges (MDCs) are generated to investigate these issues in the context of ET. Here we present the results of the first published comprehensive analysis of a recent ET MDC. Using a weakly modeled search algorithm, we recover a significant fraction (38%) of the binary black hole signals injected into the MDC, as well as ~3 binary neutron stars per day, for which we are able to estimate the chirp mass with a precision of 1%, with modest off-the-shelf computing resources. We then describe the generation of a template bank to be used by a state-of-the-art matched filtering search, aimed at covering the same search space currently explored by LIGO and Virgo, and discuss its performance and implications in terms of computing cost.
Speaker: Adrian Macquet -
233
Fast and accurate parameter estimation of high-redshift sources with the Einstein Telescope
The Einstein Telescope (ET) and other third-generation (3G) gravitational wave (GW) detectors will be key instruments for detecting gravitational waves (GWs) in the coming decades. However, analyzing the data and estimating source parameters will be challenging, especially given the large number of expected detections—between $10^4$ and $10^5$ per year—which makes current methods based on stochastic sampling impractical. In this work, we use DingoIS to perform Neural Posterior Estimation (NPE) of high-redshift events detectable with ET. NPE is a likelihood-free inference technique that leverages normalizing flows to approximate posterior distributions. After training, inference is fast, requiring only a few minutes per source, and accurate, as corrected through importance sampling and validated against standard inference methods like Bilby. We process 1000 high-redshift short-lived binary black holes (BBHs) and achieve an average sample efficiency of $\sim 13\%$, which increases to $\sim 20\%$ if we consider only sources merging at redshift $z > 10$. To confirm previous findings on ET ability to estimate parameters for high-redshift sources, we compare NPE results with predictions from the Fisher information matrix (FIM) approximation. We find that FIM underestimates sky localization errors by a factor of $> 8$, as it does not capture the multimodalities in sky localization introduced by the geometry of the triangular detector. On the contrary, FIM overestimates the uncertainty in luminosity distance by a factor of $\sim 3$ on average when the injected luminosity distance $d^{\mathrm{inj}}_{\mathrm{L}} > 10^5$ Mpc, further confirming that ET will be particularly well suited for studying the early Universe.
Speaker: Dr Filippo Santoliquido (Gran Sasso Science Institute (GSSI)) -
234
Overlapping signals in 3G detectors: an approach based on Transformers
Third-generation ground-based gravitational wave detectors such as the Einstein Telescope are expected to significantly advance our understanding of compact binary coalescences. One of the most critical challenges in data analysis for the Einstein Telescope is that of overlapping signals. With a tenfold improvement in sensitivity, the Einstein Telescope will be able to detect binary black hole and binary neutron star coalescences with expected rates of up to ~10⁵ events per year. Moreover, the extended range toward lower frequencies will allow the detector to observe these signals for longer durations compared to current-generation detectors. While this creates the opportunity to deepen our knowledge of these sources, detectable signals will inevitably overlap. This poses a severe challenge to parameter estimation analysis pipelines. We need a faster, unbiased parameter estimation strategy.
In this talk, we will describe a promising solution to address this challenge: a deep learning approach that combines the power of two state-of-the-art machine learning architectures, Transformers and Normalizing Flows. In particular, we present the first application of a Transformer encoder for gravitational wave data analysis. This architecture is capable of capturing complex, varying-range dependencies, and we use it to extract the information in the data. We then employ Normalizing Flows to estimate the high-dimensional posterior distributions of the overlapped signals.
We will present the results from training this network architecture, demonstrating its effectiveness in handling three overlapping signals simultaneously, and discussing how this deep learning method represents a promising solution to the problem, along with its potential extensions and improvements.Speaker: Lucia Papalini (University of Pisa and INFN Pisa) -
235
Scalable Bayesian Inference for 3G Gravitational Wave Observatories: Leveraging Normalizing Flows and Hardware Acceleration
Third-generation (3G) gravitational wave (GW) observatories will unveil a cosmic orchestra, detecting thousands of sources annually. However, their increased detection rate poses a major challenge for data analysis. Existing, widely used techniques to obtain the source parameters are prohibitively expensive, creating a bottleneck for extracting scientific insights from 3G detector data. We present ongoing developments of an efficient data analysis pipeline that leverages normalizing flows and hardware accelerators. As an example, we demonstrate Bayesian inference of GW data from binary neutron star mergers, their electromagnetic counterparts, and their implications for nuclear physics, reducing the computational cost from months to a couple of hours. Moreover, our approach enables joint parameter estimation of overlapping GW signals within a few hours. Our methods hold strong promise in meeting the scalability demands of 3G GW detectors, enabling efficient and comprehensive data analysis for future observatories.
Speaker: Thibeau Wouters (Utrecht University)
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229
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Social Dinner Palazzo Re Enzo - Piazza del Nettuno, 1, 40124 Bologna BO, Italy
Palazzo Re Enzo - Piazza del Nettuno, 1, 40124 Bologna BO, Italy
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Plenary Plenary Room
Plenary Room
Welcome + ET Status
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236
Welcome by Deputy Rector of the University of BolognaSpeaker: Prof. Simona Tondelli
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237
Welcome by the Vice President of INFNSpeaker: Prof. Marco Pallavicini
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238
Welcome by President of INAFSpeaker: Prof. Roberto Ragazzoni
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239
Welcome by the President of INGVSpeaker: Dr Fabio Florindo
- 240
- 241
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242
ET science (blue book)Speaker: Michele Maggiore
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243
OSB work for the Task ForceSpeakers: Mikhail Korobko, Ulyana Dupletsa (GSSI)
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244
ET Coordinators UpdateSpeakers: Antonio Zoccoli (INFN), Jorgen D'Hondt
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236
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Coffee break
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Plenary Plenary Room
Plenary Room
Welcome + ET Status
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245
LISASpeaker: Jonathan Gair
- 246
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247
KM3NeTSpeaker: Marco Circella
- 248
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249
Cosmic Explorer
(remote)
Speaker: Matthew Evans
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245
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GROUP PHOTO
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Lunch
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Lunch meeting: CB
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Plenary Plenary Room
Plenary Room
Welcome + ET Status
- 250
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251
ETO Design Task Force updateSpeaker: Fiodor Sorrentino
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252
ETO PO update: “The Project Office activities, working together...”Speaker: Alessandro Variola (Istituto Nazionale di Fisica Nucleare)
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253
Activities of the ETO Engineering DepartmentSpeaker: Patrick Werneke
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254
ETO Directors' updateSpeakers: Andreas Freise, Fernando Ferroni (INFN Roma 1)
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Coffee break
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Plenary Plenary Room
Plenary Room
Welcome + ET Status
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255
Specific Boards - EIBSpeakers: Patrice Verdier (IP2I Lyon - IN2P3), Stefano Bagnasco
- 256
- 257
- 258
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255
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Public Conference (in italian) Cinema Modernissimo - Piazza Re Enzo, 40125 Bologna BO, Italy
Cinema Modernissimo - Piazza Re Enzo, 40125 Bologna BO, Italy
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Plenary Plenary Room
Plenary Room
Welcome + ET Status
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259
SCB Sessions SummarySpeakers: Andreas Rietbrock (Geophysical Institute, Karlsruhe Institute of Technology, Germany), Andreas Rietbrock
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260
Sites - EMRSpeaker: Theo Reinders (Nikhef)
- 261
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262
Sites - LusatiaSpeaker: Günther Hasinger
- 263
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264
ET Data - ET Data Access Policy and its implementationSpeaker: Michele Punturo (INFN)
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259
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Coffee break
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Plenary Plenary Room
Plenary Room
Welcome + ET Status
- 265
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266
Einstein Telescope Communications: New Image, New Website, New Momentum
In recent months, the Einstein Telescope Preparatory Phase (ET-PP) communication group has undertaken several key initiatives to strengthen the project’s visibility, cohesion, and engagement with diverse audiences. We will present the newly developed ET webpage, designed to serve as a central, accessible platform for sharing updates, project milestones, and outreach materials. We will also highlight complementary activities carried out by the group, including improved coordination across internal and external communication channels and the strategic expansion of our social media presence — now including Instagram, LinkedIn, and Bluesky, in addition to Facebook. Guidance on the correct use of the recently implemented visual identity will also be provided. These efforts aim to support the scientific goals of the ET project by fostering stronger connections with stakeholders, the broader research community, and the public.
Speaker: Yuliya Hoika (University of Warsaw) -
267
Poster award talk by previous prize winner (Seismic Attenuation for ET)Speaker: Francesca Spada
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268
Announcement of Bologna Symposium Poster Prize winners
- 269
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End of ET Symposium
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