The Dynamics of Seed Black Holes in the First Galaxies
Abstract
The discovery of bright quasars at redshift z≥6 in the Sloan Digital Sky Survey (SDSS) implies that black holes (BHs) as massive as 10^9 solar masses were already assembled within 1 Gyr. Generically, these SMBHs are thought to have assembled by mergers with other BHs and by gas accretion onto less massive seed BHs. One candidate of such seed BHs are Population III (Pop III) stellar remnants. In order to map out plausible scenarios such massive objects form from Pop III remnants, we run a cosmological adaptive refinement mesh simulation of an overdense region of about 300 Mpc^3, which forms a few 10^9 solar mass dark matter halos and over 13000 Pop III stars by redshift 15. Then we focus on one of these massive halos, containing 20 Pop III stellar remnants, to study the dynamical behavior of these BH seed candidates. Here we report on the evolution of the orbital properties of stellar-mass seed BHs in one of the first galaxies. They are distributed throughout the halo, creating a swarm of BHs, gradually falling toward the halo center through dynamical friction. From these characteristics, we estimate the BH merger rate in this particular galaxy, which is an important quantity to assess during the early buildup of massive BHs.
- Publication:
-
American Astronomical Society Meeting Abstracts #225
- Pub Date:
- January 2015
- Bibcode:
- 2015AAS...22534712S