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Two-phase model for black hole feeding and feedback

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journal contribution
posted on 13.10.2015, 11:26 by Sergei Nayakshin
We study effects of active galactic nucleus (AGN) feedback outflows on multiphase inter stellar medium (ISM) of the host galaxy. We argue that supermassive black hole (SMBH) growth is dominated by accretion of dense cold clumps and filaments. AGN feedback outflows overtake the cold medium, compress it, and trigger a powerful starburst – a positive AGN feedback. This predicts a statistical correlation between AGN luminosity and star formation rate at high luminosities. Most of the outflow's kinetic energy escapes from the bulge via low-density voids. The cold phase is pushed outward only by the ram pressure (momentum) of the outflow. The combination of the negative and positive forms of AGN feedback leads to an M-σ relation similar to the result of King. Due to porosity of cold ISM in the bulge, SMBH influence on the low density medium of the host galaxy is significant even for SMBH well below the M-σ mass. The role of SMBH feedback in our model evolves in space and time with the ISM structure. In the early gas rich phase, SMBH accelerates star formation in the bulge. During later gas poor (red-and-dead) phases, SMBH feedback is mostly negative everywhere due to scarcity of the cold ISM.

History

Citation

Monthly Notices of the Royal Astronomical Society, 2014, 437 (3), pp. 2404-2411 (8)

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Publisher

Oxford University Press (OUP)

issn

0035-8711

eissn

1365-2966

Acceptance date

22/10/2013

Copyright date

2013

Available date

13/10/2015

Publisher version

http://mnras.oxfordjournals.org/content/437/3/2404

Language

en