Multiscale mass transport in z ∼6 galactic discs: fuelling black holes
Author
dc.contributor.author
Prieto Brito, Joaquín
Author
dc.contributor.author
Escala Astorquiza, Andrés
Admission date
dc.date.accessioned
2017-01-03T20:32:15Z
Available date
dc.date.available
2017-01-03T20:32:15Z
Publication date
dc.date.issued
2016
Cita de ítem
dc.identifier.citation
MNRAS 460, 4018–4037 (2016)
es_ES
Identifier
dc.identifier.other
10.1093/mnras/stw1285
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/142242
Abstract
dc.description.abstract
By using Adaptive Mesh Refinement cosmological hydrodynamic N-body zoom-in simulations,
with the RAMSES code, we studied the mass transport processes on to galactic nuclei
from high redshift up to z ∼6. Due to the large dynamical range of the simulations, we were
able to study the mass accretion process on scales from ∼50 kpc to ∼few 1 pc. We studied
the black hole (BH) growth on to the Galactic Centre in relation with the mass transport
processes associated to both the Reynolds stress and the gravitational stress on the disc. Such
methodology allowed us to identify the main mass transport process as a function of the scales
of the problem. We found that in simulations that include radiative cooling and supernovae
feedback, the supermassive black hole (SMBH) grows at the Eddington limit for some periods
of time presenting fEDD ≈ 0.5 throughout its evolution. The α parameter is dominated by
the Reynolds term, αR, with αR 1. The gravitational part of the α parameter, αG, has an
increasing trend towards the Galactic Centre at higher redshifts, with values αG ∼1 at radii
few 101 pc contributing to the BH fuelling. In terms of torques, we also found that gravity
has an increasing contribution towards the Galactic Centre at earlier epochs with a mixed
contribution above ∼100 pc. This complementary work between pressure gradients and gravitational
potential gradients allows an efficient mass transport on the disc with average mass
accretion rates of the order of ∼few 1 M yr−1. These levels of SMBH accretion rates found
in our cosmological simulations are needed in all models of SMBH growth that attempt to
explain the formation of redshift 6–7 quasars.