Gravitational-wave dark sirens as astrophysical probes: inferring galaxy-merger relations and identifying individual hosts
Year: 2026
Type: preprint
Abstract: Gravitational-wave (GW) ``dark siren'' techniques, namely the statistical association of GW events with a galaxy catalog, have so far been used as a cosmological tool. Yet this association carries distinctive astrophysical information that remains unused---specifically, how compact binaries populate galaxies and the identities of individual hosts. In this work, we turn the dark-siren program into an astrophysical probe by inferring both simultaneously within a single hierarchical framework. The method reduces the many potential hosts to a compact, probabilistically ranked target list, providing a direct follow-up decision tool. Applied blindly to GW170817, it recovers NGC~4993 as the highest-ranked host and constrains the galaxy luminosity weighting, mildly favoring non-uniform host weights. Fixing the galaxy weighting can instead degrade host identification and even favor the wrong host. This framework recasts dark sirens as a potentially unique probe of the astrophysics of electromagnetically dark compact-binary mergers.
Source: arXiv (Cornell University)
Authors: Agapito, Alessandro, Mancarella, Michele
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, Aix-Marseille Université, National Research Foundation, Ministry of Education, Culture, Sports, Science and Technology, Academia Sinica, Centre National de la Recherche Scientifique, Istituto Nazionale di Fisica Nucleare, Ministry of Science and ICT, South Korea, National Science and Technology Council, Science and Technology Facilities Council, Japan Society for the Promotion of Science, H2020 European Research Council
Award: G1954085670
OpenAlex ID: W7214966350