First measurement of the Hubble constant from a dark standard siren using the Dark Energy Survey Galaxies and the LIGO/Virgo binary–black-hole merger GW170814
Soares-Santos, M and Palmese, A and Siellez, K and The LIGO Scientific Collaboration and the Virgo Collaboration, First measurement of the Hubble constant from a dark standard siren using the Dark Energy Survey Galaxies and the LIGO/Virgo binary-black-hole merger GW170814, The Astrophysical Journal Letters, 876, (1) Article L7. ISSN 2041-8205 (2019) [Refereed Article]
We present a multi-messenger measurement of the Hubble constant H0 using the binary–black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in H0=75+40-32km s-1 Mpc-1, which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s-1 Mpc-1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s-1 Mpc-1, we find H0=78+96-24km s-1 Mpc-1, (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H0.