Speaker
Description
The enhanced sensitivity achieved by the LIGO-Virgo-KAGRA (LVK) collaboration has significantly increased the number of gravitational wave (GW) detections, along with improvements in sky localization and luminosity distance estimation. These advances enable the use of dark standard sirens as tools for cosmological probing. Dark sirens are GW events without the identification of an electromagnetic counterpart, where source redshifts are inferred statistically by assigning probabilities to galaxies within the three-dimensional localization volume based on spatial distribution.
As third-generation GW detectors are expected to observe tens of thousands of events per year, percent-level precision in cosmological parameters becomes attainable. This makes it essential to understand and identify systematic uncertainties inherent in the dark siren framework. In this study, we analyze three key sources of bias: (1) inaccuracies in the assumed weighting schemes for potential host galaxies, (2) the incompleteness of galaxy catalogs limited by apparent magnitude, and (3) the galaxies' photometric redshift errors.
Our analysis demonstrates that such biases can be mitigated through: (1) constructing volume-limited samples from incomplete galaxy catalogs, and (2) improving the modeling of host-galaxy weighting, particularly in cases with well-localized GW events. Under the assumption of perfect redshift measurements and using stellar mass as a tracer for host probability, we find that the Hubble constant can be constrained to ~3% (1%) precision following 8 (3) years of LVK observations at O4 (O5) sensitivity.
