supermassive black holes and their environments

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Supermassive Black Holes and their Environments. J örg M. Colberg with Tiziana Di Matteo Carnegie-Mellon University. The Simulation. Simulation just introduced by Tiziana 3,547 BHs at z=1 , plus all their progenitors (4.5m total) Using haloes and full particle sets at some redshifts. - PowerPoint PPT Presentation


  • Supermassive Black Holes and their Environments Jrg M. Colbergwith Tiziana Di MatteoCarnegie-Mellon University

  • The SimulationSimulation just introduced by Tiziana3,547 BHs at z=1, plus all their progenitors (4.5m total) Using haloes and full particle sets at some redshifts

  • So what does a BH merger tree look like?

  • The Black Hole-Halo ConnectionMost massive haloes host most massive BHsAt z=1, most active BHs live in haloes of mass 1012 Msun or lessOpen circles: satellites, with (generally) low accretion

  • The next step: BHs-Haloes-EnvironmentSatellite BHs in massive haloeslow-mass haloesand low-mass BHs in underdense regionsLow-mass haloes/BHs in wide range of environments!

  • A bit of an aside: When do BHs form?Hierarchical growth along this lineMost massive BHs do not followhierarchical formation scenario

  • More on environments and evolutionz=1z=3satsreducedaccretion

  • Smallest BHs oblivious of environmentLarge number of m < 107 Msun BHs in 1011 1012 Msun haloes grow very slowly,independent of environment

  • BH Assembly: Mergers vs. AccretionOnly for the largest BHs, environmental effect on mergers vs. accretion: BHs in denser regions have slightly higher fractions of merged mass

  • SummaryThe most massive BHs live in the most massive haloes etc.BUT the most massive z=1 BHs arent necessarily the most massive BHs at higher redshifts (c.f. Tizianas talk)Environmental dependencies strongest for massive (> 108 Msun) BHs, both in mass, accretion rate, and mass assembly, and for satellite BHs (whose behaviour is consistent with their parent subhaloes having lost all their gas after infall into the larger halo)Most small (< 107 Msun) BHs grow thru very slow accretion, with no mergers, independent of environment, with high zf > 2.5Massive (> 108 Msun) BHs form anti-hierarchically, whereas smaller BHs form hierarchically