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Growth and activity of black holes in galaxy mergers with varying mass ratios

Capelo, Pedro R. ; Volonteri, Marta ; Dotti, Massimo ; Bellovary, Jillian M. ; Mayer, Lucio ; Governato, Fabio

In: Monthly Notices of the Royal Astronomical Society, 2015, vol. 447, no. 3, p. 2123-2143

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    Titre
    • Growth and activity of black holes in galaxy mergers with varying mass ratios
    Auteur
    • Capelo, Pedro R.. Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA
    • Volonteri, Marta. Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA
    • Dotti, Massimo. Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano Bicocca, Piazza della Scienza 3, I-20126 Milano, Italy
    • Bellovary, Jillian M.. Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA
    • Mayer, Lucio. Institute for Computational Science, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
    • Governato, Fabio. Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA
    Type de document
    • Postprint
    Langue
    • Inglese
    Publié dans
    • Monthly Notices of the Royal Astronomical Society, 2015, vol. 447, no. 3, p. 2123-2143. Oxford University Press
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:289209
    Summary
    We study supermassive black holes (BHs) in merging galaxies, using a suite of hydrodynamical simulations with very high spatial (∼10 pc) and temporal (∼1Myr) resolution, where we vary the initial mass ratio, the orbital configuration, and the gas fraction. (i) We address the question of when and why, during a merger, increased BH accretion occurs, quantifying gas inflows and BH accretion rates. (ii) We also quantify the relative effectiveness in inducing active galactic nuclei activity of merger-related versus secular-related causes, by studying different stages of the encounter: the stochastic (or early) stage, the (proper) merger stage, and the remnant (or late) stage. (iii) We assess which galaxy mergers preferentially enhance BH accretion, finding that the initial mass ratio is the most important factor. (iv) We study the evolution of the BH masses, finding that the BH mass contrast tends to decrease in minor mergers and to increase in major mergers. This effect hints at the existence of a preferential range of mass ratios for BHs in the final pairing stages. (v) In both merging and dynamically quiescent galaxies, the gas accreted by the BH is not necessarily the gas with low angular momentum, but the gas that loses angular momentum