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| Paper: |
Gas Accretion onto a Supermassive Black Hole: A Step to Model AGN Feedback |
| Volume: |
460, AGN Winds in Charleston |
| Page: |
245 |
| Authors: |
Nagamine, K.; Barai, P.; Proga, D. |
| Abstract: |
We study gas accretion onto a supermassive black hole (SMBH) using
the 3D SPH code GADGET-3 on scales of 0.1–200 pc. First we test
our code with the spherically symmetric, adiabatic Bondi accretion
problem. We find that our simulation can reproduce the expected Bondi
accretion flow very well for a limited amount of time until the effect
of the outer boundary starts to be visible. We also find artificial
heating of gas near the inner accretion boundary due to the artificial
viscosity of SPH. Second, we implement radiative cooling and heating
due to X-rays, and examine the impact of thermal feedback by the
central X-ray source. The accretion flow roughly follows the Bondi
solution for low central X-ray luminosities; however, the flow starts
to exhibit non-spherical fragmentation due to the thermal instability for
a certain range of central LX, and a strong overall outflow
develops for greater LX. The cold gas develops filamentary
structures that fall into the central SMBH, whereas the hot gas tries
to escape through the channels in between the cold filaments. Such
fragmentation of accreting gas can assist in the formation of clouds
around AGN, induce star-formation, and contribute to the observed
variability of narrow-line regions. |
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