Supermassive black hole accretion and feedback play central role in the evolution of galaxies, groups, and clusters. I review how AGN feedback is tightly coupled with the formation of multiphase gas and the newly probed chaotic cold accretion (CCA). In a turbulent and heated atmosphere, cold clouds and kpc-scale filaments condense out of the plasma via thermal instability and rain toward the black hole. In the nucleus, the recurrent chaotic collisions between the cold clouds, filaments, and central torus promote angular momentum cancellation or mixing, boosting the accretion rate up to 100 times the Bondi rate. The rapid variability triggers powerful AGN outflows, which quench the cooling flow and star formation without destroying the cool core. The AGN heating stifles the formation of multiphase gas and accretion, the feedback subsides and the hot halo is allowed to cool again, restarting a new cycle. Ultimately, CCA creates a symbiotic link between the black hole and the whole host via a tight self-regulated feedback which preserves the gaseous halo in global thermal equilibrium throughout cosmic time.

The self-regulated AGN feedback loop: the role of chaotic cold accretion / Gaspari, Massimo. - 11:S319(2016), pp. 17-20. (Intervento presentato al convegno 319th Symposium of the International-Astronomical-Union (IAUS) / 320th Symposium of the International-Astronomical-Union (IAUS) tenutosi a Honolulu, United States nel 11-14 August, 2015) [10.1017/S1743921315010455].

The self-regulated AGN feedback loop: the role of chaotic cold accretion

GASPARI, MASSIMO
2016

Abstract

Supermassive black hole accretion and feedback play central role in the evolution of galaxies, groups, and clusters. I review how AGN feedback is tightly coupled with the formation of multiphase gas and the newly probed chaotic cold accretion (CCA). In a turbulent and heated atmosphere, cold clouds and kpc-scale filaments condense out of the plasma via thermal instability and rain toward the black hole. In the nucleus, the recurrent chaotic collisions between the cold clouds, filaments, and central torus promote angular momentum cancellation or mixing, boosting the accretion rate up to 100 times the Bondi rate. The rapid variability triggers powerful AGN outflows, which quench the cooling flow and star formation without destroying the cool core. The AGN heating stifles the formation of multiphase gas and accretion, the feedback subsides and the hot halo is allowed to cool again, restarting a new cycle. Ultimately, CCA creates a symbiotic link between the black hole and the whole host via a tight self-regulated feedback which preserves the gaseous halo in global thermal equilibrium throughout cosmic time.
2016
319th Symposium of the International-Astronomical-Union (IAUS) / 320th Symposium of the International-Astronomical-Union (IAUS)
Honolulu, United States
11-14 August, 2015
11
17
20
Gaspari, Massimo
The self-regulated AGN feedback loop: the role of chaotic cold accretion / Gaspari, Massimo. - 11:S319(2016), pp. 17-20. (Intervento presentato al convegno 319th Symposium of the International-Astronomical-Union (IAUS) / 320th Symposium of the International-Astronomical-Union (IAUS) tenutosi a Honolulu, United States nel 11-14 August, 2015) [10.1017/S1743921315010455].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1338530
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