Kinetic AGN Feedback Effects on Cluster Cool Cores Simulated using SPH

BARAI, PARAMITA; GASPARI, MASSIMO; RAGONE FIGUEROA, CINTHIA; BORGANI, STEFANO; MONACO, PIERLUIGI; MURANTE, GIUSEPPE; GRANATO, GIAN LUIGI

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016 vol. 461 p. 1548 - 1567

0035-8711

We implement novel numerical models of AGN feedback in the SPH codeGADGET-3, where the energy from a supermassive black hole (BH) is coupled tothe surrounding gas in the kinetic form. Gas particles lying inside a bi-conical volumearound the BH are imparted a one-time velocity (10, 000 km/s) increment. We performhydrodynamical simulations of isolated cluster (total mass 10 14 h −1 M ⊙ ), which is ini-tially evolved to form a dense cool core, having central T 10 6 K. A BH resides at thecluster center, and ejects energy. The feedback-driven fast wind undergoes shock withthe slower-moving gas, which causes the imparted kinetic energy to be thermalized.Bipolar bubble-like outflows form propagating radially outward to a distance of a few100 kpc. The radial profiles of median gas properties are influenced by BH feedbackin the inner regions (r < 20 − 50 kpc). BH kinetic feedback, with a large value of thefeedback efficiency, depletes the inner cool gas and reduces the hot gas content, suchthat the initial cool core of the cluster is heated up within a time 1.9 Gyr, wherebythe core median temperature rises to above 10 7 K, and the central entropy flattens.Our implementation of BH thermal feedback (using the same efficiency as kinetic),within the star-formation model, cannot do this heating, where the cool core remains.The inclusion of cold gas accretion in the simulations produces naturally a duty cycleof the AGN with a periodicity of 100 Myr.