Formation and Coalescence of Cosmological Supermassive Black Hole Binaries in Supermassive Star Collapse
Tuesday 30 September 2014
to 14:30 at
Christian Reisswig (Caltech)
The overwhelming observational evidence for supermassive black holes
in the early Universe at high redshifts z>7 produces a serious
problem: how could these black holes have formed? The growth via accretion
onto collapsed Population III stars is challenging within the available short
timeframe. A possible alternative pathway for supermassive black hole
formation at high redshifts is the collapse of a supermassive star that may
have formed in the direct collapse of a primordial gas cloud.
We self-consistently simulate the collapse of rapidly rotating supermassive
stars from the onset of collapse using three-dimensional general-relativistic
hydrodynamics with fully dynamical spacetime evolution.
We show that seed perturbations in the progenitor can lead to the formation of
a system of two high-spin supermassive black holes,
which inspiral and merge under the emission of powerful gravitational
radiation. The gravitational-wave signals could be observed at redshifts z>10
with the DECIGO or Big Bang Observer gravitational-wave observatories,
assuming supermassive stars in the mass range 10^4-10^6 Msol.
The potential detection of such signals may inform cosmology about the
formation process of supermassive black holes at high redshifts.