Simulating Supermassive Black Hole Accretion: Spherical Flow to Cold Clumps and Hot Bubbles
Dr Paramita Barai
University of Nevada, Las Vegas
Active galaxies are believed to host a supermassive black hole (SMBH) at their center. Accretion and feedback from these BHs play an important role in the formation and evolution of galaxies, also affecting the intergalactic environments. Modeling AGN feedback in galaxy simulations is computationally challenging, as small-scale (< pc) BH physics needs to be incorporated into Mpc-scale cosmological simulations. Existing subgrid models of AGN feedback assumes the Bondi-Hoyle accretion rate, with ad-hoc choice of parameter values. Our initial motivation has been to numerically test such an assumption, using a smoothed particle hydrodynamics code. We perform simulations of a spherical distribution of gas, within 0.1 - 200 pc, accreting onto a central SMBH (the Bondi problem). We have included radiative processes in our simulations: heating by a central X-ray corona and radiative cooling. I will present results from such simulations done in collaboration with Prof. Daniel Proga at UNLV. I will end with our recent results of the formation of cold clumps and hot bubbles in the BH accretion flow, caused by various instabilities.
Date: Mardi, le 21 juin 2011 Heure: 12:00 Lieu: Université Laval Pavillon Alexandre-Vachon, local 1661