Galaxy fields of LISA massive black hole mergers in a simulated universe

Abstract

Laser Interferometer Space Antenna (LISA) will extend the search for gravitational waves (GWs) at 0.1 − 100 mHz where loud signals from coalescing binary black holes of 104 − 107 M are expected. Depending on their mass and luminosity distance, the uncertainty in the LISA sky-localization decreases from hundreds of deg2 during the inspiral phase to fractions of a deg2 after the merger. By using the semi-analytical model L-Galaxies applied to the Millennium-I merger trees, we generate a simulated universe to identify the hosts of z ≤ 3 coalescing binaries with total mass of 3 × 105, 3 × 106, and 3 × 107 M, and varying mass ratio. We find that, even at the time of merger, the number of galaxies around the LISA sources is too large ( < 1, all LISA fields at merger are populated by <~ 1.