Dynamics of black holes, AGN activity, and star formation in galaxy mergers

Seminar Date: 
28 Jul 2015 - 14:00
Pedro Capelo
Institute for Computational Science, University of Zürich, Switzerland

I present the latest results from a suite of high-resolution hydrodynamical simulations of mergers between two late-type galaxies, in which I vary the mass ratio, gas fraction, and orbital configuration, and where I include realistic descriptions of cooling, stellar and black hole (BH) feedback, and star formation. I study both the evolution of the central BHs and the fate of the galaxies themselves, from the moment the two galaxies can still be considered in isolation to coalescence. In the first part of my talk, I focus on the dynamics of the central stellar nuclei during these galactic encounters and on the importance of central star formation in determining the time-scale of BH pairing. I then shift the focus to the accretion and growth of the central BHs, with emphasis on the role of the gas angular momentum: I examine which mergers preferentially trigger AGN activity, distinguish between merger-related and secular-related accretion, and trace the resultant evolution of the BH mass ratios in the pairing process. I further discuss the link between BH accretion and galactic star formation, and conclude with preliminary results on the formation/destruction of molecular gas and H2-based star formation in isolated galaxies.