Feedback effect on the observable properties of z > 6 AGN
Date Issued
2022
Author(s)
•
Di Mascia,Fabio
•
Gallerani, Simona
•
Zana, Tommaso
•
Ferrara, Andrea
•
Carniani, Stefano
•
Abstract
Active galactic nuclei (AGN) feedback has a major impact onto the
supermassive black-hole (SMBH) growth, the properties of the host galaxies, and
their cosmic evolution. We investigate the effects of different kinetic
feedback prescriptions on the observable properties of AGN and their host
galaxies at $z>6$ in a suite of zoom-in cosmological simulations. We find that
kinetic feedback decreases the column density of the interstellar medium (ISM)
in the host galaxy by up to a factor of $\approx10$, especially when the SMBHs
reach high accretion rates ($\approx10-30\,\mathrm{M_\odot\,yr^{-1}}$). In
particular, kinetic feedback is required to extend the ISM size to $>1$ kpc and
match the observed sizes of the gas reservoirs in $z>6$ AGN host galaxies.
Moreover, it produces unobscured lines of sight along which the AGN can be
detected in the rest-frame UV band with magnitudes consistent with observed
values of $z>6$ AGN. The assumed geometry of the outflow plays an important
role in shaping the observed properties of high-redshift AGN. We find that a
biconical geometry is favored over a spherical one to reproduce the observed
properties, but it overestimates the number of multiple AGN systems detectable
in X-ray observations. This result suggests that simplistic BH seeding recipes
widely employed in cosmological simulations produce too many X-ray detectable
multiple AGN at $z=6-7$, thus soliciting the adoption of more physically
motivated seeding prescriptions.
Volume
514
Issue
2
Start page
1672
Issn Identifier
0035-8711
Rights
open.access
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