Contributed Talk - Splinter SMBHs

Wednesday, 23 September 2020, 09:35   (virtual room K)

Super-Eddington dusty gas accretion onto intermediate-mass seed black holes

Daisuke Toyouchi, Takashi Hosokawa, Kohei Inayoshi, Rolf Kuiper
Kyoto Univ., Peking Univ.

Super-Eddington gas accretions onto seed black holes are a possible mechanism for forming supermassive black holes (SMBHs) with about one billion solar mass discovered at z ~ 7. Mass transportation from pc scale circumnuclear disks (CNDs) to their central BHs has been investigated using three-dimensional radiation hydrodynamics (RHD) simulations. However, previous works have assumed large BH mass of > 10^6 Msun and specific gas metallicities, Z = 0 or Zsun. Therefore, in this study, we explore dusty gas accretions onto intermediate-mass seed BHs with 10^4 Msun in the low-metallicity environments, Z < 0.1 Zsun, with 3D RHD simulations which solve hydrodynamics with self-gravity of gas, radiative transfers of ionizing photons and thermal emissions from dust grains, and non-equilibrium chemistry self-consistently. Our simulations show that higher gas densities and metallicities lead to colder and geometrically thinner CNDs, consequently avoiding significant photoevaporation of accreting gas. In particular, super-Eddington accretions occur when the metal-enriched gas with Z > 0.01 Zsun goes into the CND regions at inflow rates 100 times higher than the Eddington one. In this talk, based on these results, we will discuss SMBH formation sites in the early universe.