Probing the Universe’s expansion with multi-messenger astronomy

Antonella Palmese (Carnegie Mellon University)

April 22, 2024

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Abstract: Thanks to the synergies between gravitational wave (GW) experiments, such as LIGO/Virgo/KAGRA, and electromagnetic observations of transients and galaxies, a variety of novel cosmological measurements has recently become possible. Several of these measurements rely on the use of GW events as “standard sirens”. Following the detection of the first electromagnetic counterpart to a GW event, GW170817, the first “bright” standard siren measurement has been performed. We continue searching for optical counterparts to enable more bright siren analyses with the Gravitational Wave Multi-Messenger Astronomy DECam Survey (GW-MMADS), which I will introduce. Standard siren measurements for “dark” events, i.e. without a confirmed electromagnetic counterpart, can also been performed, using cross-correlations with galaxy or Active Galactic Nuclei catalogs. In this talk I will present our latest bright and dark standard siren measurements, and also provide forecasts for multi-messenger cosmology in the upcoming years.