GdR Gravitational Waves WG joint meeting: Source populations and Multi-messenger Astronomy

Liste des Contributions

4. Invited talk: Multimessenger in the LIGO-Virgo-KAGRA collaboration

Thomas JACQUOT (IJCLAB)

16/11/2026 14:00

Multimessenger follow-up and alert systems

MultiMessenger astronomy is some of the most exciting science that we can do with gravitational waves. The LIGO-Virgo-KAGRA (LVK) Collaboration searches for coincident gravitational wave event with an external counterpart and searches for coincident triggers in multiple external data channels (e.g. Neutrinos, Gamma Ray Bursts, Fast Radio Bursts, Soft Gamma Repeaters, pulsar glitches). Searches...

2. Contributed talk: Multimessenger astronomy with sub-solar mass neutron stars

Camille Allan (IP2I)

16/11/2026 14:30

Multimessenger follow-up and alert systems

The existence of sub-solar mass neutron stars remains uncertain, despite several theoretical scenarios for their formation. Assuming that such objects exist, could they be observed through multimessenger astronomy? The detection of a sub-solar mass neutron star through both gravitational-wave and electromagnetic signals would provide valuable insights into nuclear physics and the formation of...

15. Contributed talk: ET-WST synergy for next generation gravitational wave multi-messenger observations

Dr Sofia Bisero (Irfu, CEA-Saclay), Sofia Bisero (GEPI, Observatoire de Paris, Université PSL, CNRS)

16/11/2026 14:50

Multimessenger follow-up and alert systems

Third generation (3G) gravitational wave (GW) interferometers such as the Einstein Telescope (ET) and Cosmic Explorer (CE) will explore a larger volume of the Universe with respect to now, detecting up to 10$^{5}$ binary neutron star system mergers (BNS) per year and revolutionizing GW multi-messenger (MM) astrophysics. The error volume on the sky position of such BNS will be large and finding...

16. Invited talk: The Vera C. Rubin Observatory in Operation: First Results and Prospects for Multi-Messenger Astronomy

Roman Le Montagner

16/11/2026 15:40

Multimessenger follow-up and alert systems

After first light in 2025, the Vera C. Rubin Observatory formally began the 10-year Legacy Survey of Space and Time (LSST) on 29 June 2026. The public alert stream has been running since February 2026. In this talk I will give an overview of Rubin’s status and early science. I will start with the observatory, the survey strategy and the data products released so far, including the Data...

6. Contributed talk: KM3NeT alerts system

Jean-gregoire Ducoin (CPPM)

16/11/2026 16:10

Multimessenger follow-up and alert systems

KM3NeT is dedicated to detect and study neutrinos from distant astrophysical sources as well as from our own atmosphere. It is composed of the ARCA detector, located offshore Portopalo di Capo Passero, Sicily, Italy, at a depth of about 3,450 m and the ORCA detector, located at a depth of about 2,450 m, offshore Toulon, France. KM3NeT is under construction but already operational and its...

11. Contributed talk: Follow-up of gravitational events

Damien Turpin (CEA), Sarah ANTIER (IJCLAB)

16/11/2026 16:30

Multimessenger follow-up and alert systems

Due to the upcoming IR1 GW run, follow-up campaign will restart to identify the optical counterpart of GW events. After briefly presenting the alert system for IR1, I will come back to observing strategies for IR1, especially since LSST and SVOM are both taking data.

14. Contributed talk: Benchmarking the expected performance of Bayesian parameter inference on Kilonovae

Thomas Hussenot

16/11/2026 16:50

Multimessenger follow-up and alert systems

In the study of optical transients, parameter inference is a part of the process of extracting physical information, i.e. constraints on the source's characteristics, by comparing the observed lightcurves to the predictions of different astrophysical models and finding the model and parameter combination that make the closest match.
In the developing field of the study of kilonovae (KN),...

32. Invited talk: Eccentric supermassive black hole binaries and non-stationarities induced in the PTA gravitational wave background

Sara Manzini (APC - Université Paris Cité)

17/11/2026 09:00

Massive Black Hole binaries

The nanohertz gravitational wave background (GWB) observed by Pulsar Timing Arrays (PTAs) is usually modelled as a stationary, spatially correlated red noise process. Eccentric supermassive black hole binaries (SMBHBs), however, emit gravitational wave bursts at periastron passage, which can make the background non-stationary. Using a time-dependent model of the common red noise (CRN) power...

10. Contributed talk: PTA band GWB anisotropies and their cross correlation with galaxies

Martin Pijnenburg

17/11/2026 09:30

Massive Black Hole binaries

The compelling evidence for the presence of nHz gravitational waves (GWs) in pulsar timing data calls for a refinement of what can and cannot be expected beyond vanilla scenarios. Under the hypothesis of an astrophysical origin for the GWs, we discuss possible imprints left in the signal by the fact the Universe is inherently clustered, with anisotropic large scale structure.
At the...

12. Contributed talk: Investigating the sensitivity of the MPTA and extended datasets to alternative gravitational wave polarisations using simulations

Jaikhomba Singha (University of Cape Town)

17/11/2026 09:50

Massive Black Hole binaries

We explore the sensitivity to alternative gravitational wave polarisations in current and future pulsar timing array (PTA) datasets. We focus on the Scalar-Transverse (ST) mode, which is not present in a purely quadrupolar (Traceless-Transverse or TT) gravitational wave background as predicted by General Relativity. Our analysis is based on the MeerKAT Pulsar Timing Array dataset, which...

13. Contributed talk: Searching for Bursts with Linear Gravitational-Wave Memory in the MPTA 4.5-Year Data Release

Dr Prerna Rana (LPC2E, Orleans, France)

17/11/2026 10:10

Massive Black Hole binaries

Close hyperbolic encounters of supermassive black holes produce Gravitational Waves (GWs) having bursts with linear memory (BWM) signature, which appears close to a ramp-like function in pulsar timing residuals. Pulsar timing arrays (PTAs) are therefore well suited to detect such events or to constrain their occurrence out to gigaparsec distances. In this talk, we present initial results from...

5. Contributed talk: Probing zombie binaries: A new window on supermassive black hole binary mergers

Hippolyte Quelquejay-Leclere (Università degli Studi di Milano-Bicocca)

17/11/2026 11:00

Massive Black Hole binaries

By monitoring the times of arrival of radio pulses from millisecond pulsars, pulsar timing arrays (PTAs) serve as unique gravitational wave (GW) laboratories in the nanohertz band. To date, the primary astrophysical sources of GWs targeted in this frequency range have been inspiraling supermassive black hole binaries (SMBHBs) on circular and eccentric orbits. In this work, we demonstrate that,...

9. Contributed talk: From MUSE Close Pairs of Galaxies to LISA: Observational Constraints on Massive Black Hole Coalescences

Loic BOCHRAWNA (Institut de Recherche en Astrophysique et Planétologie (IRAP))

17/11/2026 11:20

Massive Black Hole binaries

In the hierarchical framework of structure formation, galaxy mergers are key drivers of galaxy evolution and can lead to the formation of massive black hole binaries, whose coalescences are among the primary gravitational-wave sources expected for the future space-based detector LISA.
Predictions for massive black hole merger rates generally rely on cosmological simulations, which can...

50. Massive Black Hole binaries: discussion

Astrid Lamberts (Observatoire de la Cote d'Azur), Aurélien Chalumeau (LPC2E/OSUC), Floriane Cangemi (UPC/APC), Irina Dvorkin (Institut d'Astrophysique de Paris), Dr Marion Pillas (IAP), Olivier GODET (IRAP)

17/11/2026 11:40

Massive Black Hole binaries

Document for discussion: https://docs.google.com/document/d/1tQwanxZER_n09s1hsgsqPMMCPNp3W3lROZroBByXV4c/edit?usp=sharing

30. Invited talk: Isotropic Gravitational-Wave Background Search Results from the 4th LVK observing run

Alba ROMERO RODRIGUEZ (Laboratoire D'Annecy de Physique de Particules (LAPP))

17/11/2026 13:30

Stellar mass objects

In this talk, I will present latest results from the search for an isotropic gravitational-wave background (GWB) using data from the second and third segments of LVK's fourth observing run[1, 2]. Although no evidence for a stochastic gravitational-wave background has been found, the analysis yields improved constraints on several theoretical models and places new limits on non-standard...

1. Contributed talk: Joint multi-messenger inference of double white dwarfs with LISA

Nina Kunert (Observatoire de la Cote d'Azur)

17/11/2026 14:00

Stellar mass objects

Double white dwarfs are persistent multi-messenger sources, emitting millihertz gravitational waves detectable by LISA, while their light curves show eclipses and orbital modulations. Both signals are driven by the same orbital motion and therefore share a common orbital clock, yet they have been analyzed sequentially. We present a joint Bayesian framework that simultaneously models both...

3. Contributed talk: A deep, large-scale survey for LISA white dwarf binary candidates with the Canada-France Hawaii Telescope

Alice Perego (Observatoire de la Côte d'Azur)

17/11/2026 14:20

Stellar mass objects

Ultra-compact white dwarf binaries ($P_{\rm orb} \lesssim$ 1 hour) are invaluable probes for studying stellar and binary evolution, and will serve as prime multi-messenger targets for LISA, the future space-based gravitational wave observatory operating in the millihertz regime. Preparing for the mission launch in 2035 requires identifying the highest number of electromagnetic counterparts, in...

41. Comparing degrees of EOS knowledge in prior choices for gravitational-wave parameter estimation and equation-of-state inference for binary neutron stars (Contribution from NS-SN-Nucleosynthesis WG)

17/11/2026 14:40

Stellar mass objects

7. Contributed talk: The Parameter Space of BNS Populations: Formation Channels and Merger Rates

Mathieu VENET

17/11/2026 15:00

Stellar mass objects

Binary neutron stars (BNS) play a central role in various high-energy astrophysical phenomena,from short gamma-ray bursts to kilonovae.

Even though the number of known systems is currently relatively small, upcoming observations are expected to drastically increase the size of both Galactic and extragalactic BNS populations.

Population synthesis codes offer a powerful tool to study large...

38. Neutron stars, EOS, Multi-messenger astronomy, Population: Discussion

Astrid Lamberts (Observatoire de la Cote d'Azur), Floriane Cangemi (UPC/APC), Irina Dvorkin (Institut d'Astrophysique de Paris), Dr Marion Pillas (IAP), Matteo Bugli (UniTo - CEA Saclay), Olivier GODET (IRAP)

17/11/2026 15:20

Stellar mass objects

8. Contributed talk: Natal kicks and r-process enrichment: starting to trace binary neutron star populations in cosmological simulations

Arturo Nunez-Castineyra (Institut d'Astrophysique de Paris)

17/11/2026 16:20

Stellar mass objects

Binary neutron star (BNS) mergers are among the leading astrophysical sites of rapid neutron-capture (r-process) nucleosynthesis. However, uncertainties in binary stellar evolution, particularly natal kicks and merger delay times, complicate predictions of their contribution to galactic chemical enrichment. Natal kicks can displace BNS systems from their birth environments, potentially...

42. Inferring dense matter properties from gravitational waves (Contribution from NS-SN-Nucleosynthesis WG)

17/11/2026 16:40

Stellar mass objects

43. Contributed talk: Modelling astrophysical stochastic signals in LISA

Alexandre Toubiana (Université de Milan-Bicocca)

17/11/2026 17:00

Stellar mass objects

Unresolved Galactic binaries produce a confusion foreground that dominates over LISA’s instrumental noise in part of the millihertz band. Extragalactic binaries add a weaker stochastic background that becomes increasingly important as observations accumulate. Both components affect LISA’s sensitivity, and their spectra depend on uncertain astrophysical processes, including tides, mass transfer...