Measuring the Hubble Constant with a sample of kilonovae
  Kilonovae produced by the coalescence of compact binaries with at least one
neutron star are promising standard sirens for an independent measurement of
the Hubble constant ($H_0$). Through their detection via follow-up of
gravitational-wave (GW), short gamma-ray bursts (sGRBs) or optical surveys, a
large sample of kilonovae (even without GW data) can be used for $H_0$
contraints. Here, we show measurement of $H_0$ using light curves associated
with four sGRBs, assuming these are attributable to kilonovae, combined with
GW170817. Including a systematic uncertainty on the models that is as large as
the statistical ones, we find $H_0 = 73.8^{+6.3}_{-5.8}$\,$\mathrm{km}$
$\mathrm{s}^{-1}$ $\mathrm{Mpc}^{-1}$ and $H_0 =
71.2^{+3.2}_{-3.1}$\,$\mathrm{km}$ $\mathrm{s}^{-1}$ $\mathrm{Mpc}^{-1}$ for
two different kilonova models that are consistent with the local and
inverse-distance ladder measurements. For a given model, this measurement is
about a factor of 2-3 more precise than the standard-siren measurement for
GW170817 using only GWs.
