The Hitchhiker’s Guide to the Galaxy Catalog Approach for Dark Siren Gravitational-wave Cosmology

Abstract

We outline the “dark siren” galaxy catalog method for cosmological inference using gravitational wave (GW) standard sirens, clarifying some common misconceptions in the implementation of this method. When a confident transient electromagnetic counterpart to a GW event is unavailable, the identification of a unique host galaxy is in general challenging. Instead, as originally proposed by Schutz, one can consult a galaxy catalog and implement a dark siren statistical approach incorporating all potential host galaxies within the localization volume. Trott & Huterer recently claimed that this approach results in a biased estimate of the Hubble constant, H 0, when implemented on mock data, even if optimistic assumptions are made. We demonstrate explicitly that, as previously shown by multiple independent groups, the dark siren statistical method leads to an unbiased posterior when the method is applied to the data correctly. We highlight common sources of error possible to make in the generation of mock data and implementation of the statistical framework, including the mismodeling of selection effects and inconsistent implementations of the Bayesian framework, which can lead to a spurious bias.

Measuring the Hubble Constant of Binary Neutron Star and Neutron Star–Black Hole Coalescences: Bright Sirens and Dark Sirens

“…There is another approach that assumes the galaxies/groups are uniformly distributed in comoving volume V. Therefore, p 0 (z, Ω) could be obtained from (Soares-Santos et al 2019; Gair et al 2023)…”

Cosmography with next-generation gravitational wave detectors

“…The uncertainty in the knowledge of the true host galaxy is accounted for by statistically averaging over the redshifts from all potential host galaxies, which results in constraints on cosmological parameters using a single GW event. Such an analysis can be performed for multiple GW events, which will result in the inference of cosmological parameters with greater precision [44,[97][98][99].…”

The clustering of dark sirens' invisible host galaxies

“…If the rate of observed bright sirens continues to be relatively low, the numerical superiority of dark sirens may simply make them the most competitive GW probe of cosmology. Even if more bright sirens are observed in future, current analyses [15,[23][24][25] indicate that incorporating dark sirens can provide a significant boost to the results obtained from bright sirens alone.…”