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CG: The host galaxies of binary compact objects across cosmic time – Artale
April 19, 2022 @ 9:00 am - 9:45 am
In 2015, the first direct detection of a gravitational wave (GW) by the two ground-based LIGO interferometers opened a new era for gravitational-wave astrophysics. Since then, more than 90 events have been announced by the LIGO-Virgo-KAGRA collaboration including merging binary black holes (most of them), binary neutron stars (BNS), and black hole – neutron star binary systems. GW observations will allow us to address an impressive set of questions in cosmology and astrophysics, such as the nature of dark matter, the nature of gravity, the early Universe, and the different stellar evolution stages currently under debate. In this talk, I will focus on the properties of the host galaxies where merging compact objects form and merge. Characterizing the host galaxies’ properties of merging compact objects provides essential clues to interpreting current and future GW detections. I will discuss the probability that a galaxy hosts a compact binary coalescence according to its stellar mass and star formation rate. I will show that, at low redshift, galaxies with low specific star formation rate (sSFR < 1e-10 yr^-1) contribute significantly to the merger rate density, while those with high specific star formation rate (sSFR > 1e-10 yr^-1) dominate at z>~1. These results are crucial for low-latency searches of GW sources, reducing the number of viable host candidates. Finally, I will discuss the connection between BNS mergers and short gamma-ray burst events and the probability of afterglow detection from GW-triggered BNS mergers.