Supermassive Black Hole Seed Formation at High Redshifts: Long-Term
  Evolution of the Direct Collapse
  We use cosmological adaptive mesh refinement (AMR) code Enzo zoom-in
simulations to study the long term evolution of the collapsing gas within dark
matter (DM) halos at high redshifts. This direct collapse process is a leading
candidate for rapid formation of supermassive black hole (SMBH) seeds at high
z. To circumvent the Courant condition at small radii, we have used the sink
particle method, and focus on the evolution on scales ~0.01-10 pc. The collapse
proceeds in two stages, with the secondary runaway happening within the central
10 pc, and with no detected fragmentation. The sink particles form when the
collapsing gas requires additional refinement of the grid size at the highest
refinement level. Their mass never exceeds ~10^3 Mo, with the sole exception of
the central seed which grows dramatically to ~ 2 x 10^6 Mo in ~2 Myr,
confirming the feasibility of this path to the SMBH. The time variability of
angular momentum axis in the accreted gas results in the formation of two
misaligned disks --- a small inner disk, and a more massive, outer disk which
is inclined by ~45^o to the inner disk. The self-gravity of these disks is
heavily diluted --- both disks lie within the Roche limit of the central seed.
While the inner disk is geometrically thin and weakly asymmetric, the outer
disk flares due to turbulent motions as a result of the massive inflow along a
pair of penetrating filaments. The geometry of inflow via filaments determines
the dominant and secondary Fourier modes in this disk --- these modes have a
non-self-gravitational origin. We do not confirm that m=1 is a principal mode
that drives the inflow in the presence of a central massive object. While the
positions of the disks depend on the scale chosen to break the self-similar
collapse, the overall configuration appears to be generic, and is expected to
form when the central seed becomes sufficiently massive.
