Detection of Gravitational Waves from the Coalescence of Population-III Remnants with Advanced LIGO

The comoving mass density of massive black hole (MBH) remnants from pre-galactic star formation could have been similar in magnitude to the mass-density of supermassive black holes (SMBHs) in the present-day universe. We show that the fraction of MBHs that coalesce during the assembly of SMBHs can be extracted from the rate of ring-down gravitational waves that are detectable by Advanced LIGO. Based on the SMBH formation history inferred from the evolution of the quasar luminosity function, we show that an observed event rate of 1 per year will constrain the SMBH mass fraction that was contributed by MBHs coalescence down to a level of ~10^-6 for 20 solar mass MBH remnants (or ~10^-4 for 260 solar mass remnants).