Targeted Standard-Siren Cosmology with PTAs
Targeted pulsar-timing searches can use a known electromagnetic position to avoid the broad sky localisation and host-galaxy ambiguity that complicate standard-siren cosmology with all-sky searches.
A targeted route to cosmology
The method combines a gravitational-wave distance measurement with the redshift of a known host galaxy. By searching at a source selected from electromagnetic observations, the analysis removes the need to identify a host from a large gravitational-wave localisation region.
Using simulations informed by present observations, we show that a realistic Chinese Pulsar Timing Array data set could constrain the Hubble constant to a precision of roughly 2 km s−1 Mpc−1 for a favourable targeted source. The work also explores how multiple sources and host confusion affect the measurement.