{
  "id": "1107.4095",
  "version": "v2",
  "published": "2011-07-20T20:00:02.000Z",
  "updated": "2011-09-30T13:25:10.000Z",
  "title": "Long-term evolution of massive black hole binaries. IV. Mergers of galaxies with collisionally relaxed nuclei",
  "authors": [
    "Alessia Gualandris",
    "David Merritt"
  ],
  "comment": "22 pages, 23 figures, ApJ in press",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We simulate mergers between galaxies containing collisionally-relaxed nuclei around massive black holes (MBHs). Our galaxies contain four mass groups, representative of old stellar populations; a primary goal is to understand the distribution of stellar-mass black holes (BHs) after the merger. Mergers are followed using direct-summation N-body simulations, assuming a mass ratio of 1:3 and two different orbits. Evolution of the binary MBH is followed until its separation has shrunk by a factor of 20 below the hard-binary separation. During the galaxy merger, large cores are carved out in the stellar distribution, with radii several times the influence radius of the massive binary. Much of the pre-existing mass segregation is erased during this phase. We follow the evolution of the merged galaxies for approximately three, central relaxation times after coalescence of the massive binary; both standard, and top-heavy, mass functions are considered. The cores that were formed in the stellar distribution persist, and the distribution of the stellar-mass black holes evolves against this essentially fixed background. Even after one central relaxation time, these models look very different from the relaxed, multi-mass models that are often assumed to describe the distribution of stars and stellar remnants near a massive BH. While the stellar BHs do form a cusp on roughly a relaxation time-scale, the BH density can be much smaller than in those models. We discuss the implications of our results for the EMRI problem and for the existence of Bahcall-Wolf cusps.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2011-09-30T13:25:10.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "massive black hole binaries",
      "collisionally relaxed nuclei",
      "long-term evolution",
      "stellar-mass black holes",
      "central relaxation time"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/744/1/74",
      "journal": "The Astrophysical Journal",
      "year": 2012,
      "month": "Jan",
      "volume": 744,
      "number": 1,
      "pages": 74
    },
    "note": {
      "typesetting": "TeX",
      "pages": 22,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 919472,
      "adsabs": "2012ApJ...744...74G"
    }
  }
}