We present a measurement of the Hubble constant H _ { 0 } using the gravitational wave ( GW ) event GW190814 , which resulted from the coalescence of a 23 M _ { \odot } black hole with a 2.6 M _ { \odot } compact object , as a standard siren .
No compelling electromagnetic counterpart with associated host galaxy has been identified for this event , thus our analysis accounts for \sim 2,700 potential host galaxies within a statistical framework .
The redshift information is obtained from the photometric redshift ( photo- z ) catalog from the Dark Energy Survey .
The luminosity distance is provided by the gravitational wave sky map published by the LIGO/Virgo Collaboration .
Since this GW event has the second–smallest sky localization area after GW170817 , GW190814 is likely to provide the best constraint on cosmology from a single standard siren without identifying an electromagnetic counterpart .
Our analysis uses photo- z probability distribution functions and corrects for photo- z biases .
We also reanalyze the binary–black hole GW170814 within this updated framework .
We explore how our findings impact the H _ { 0 } constraints from GW170817 , the only GW merger associated with a unique host galaxy , and therefore the most powerful standard siren to date .
From a combination of GW190814 , GW170814 and GW170817 , our analysis yields H _ { 0 } = 69.0 ^ { +14 } _ { -7.5 } ~ { } { km~ { } s ^ { -1 } ~ { } Mpc ^ { -1 } } ( 68 % Highest Density Interval , HDI ) for a prior in H _ { 0 } uniform between [ 20 , 140 ] ~ { } { km~ { } s ^ { -1 } ~ { } Mpc ^ { -1 } } .
The addition of GW190814 and GW170814 to GW170817 improves the 68 % HDI from GW170817 alone by \sim 12 \% , showing how well–localized mergers without counterparts can provide a marginal contribution to standard siren measurements , provided that a complete galaxy catalog is available at the location of the event .