{
  "id": "astro-ph/9508070",
  "version": "v1",
  "published": "1995-08-16T23:59:22.000Z",
  "updated": "1995-08-16T23:59:22.000Z",
  "title": "Structure and Dynamics of the Coma Cluster",
  "authors": [
    "Matthew Colless",
    "Andrew M. Dunn"
  ],
  "comment": "To appear in Ap.J., 43 pages, Postscript of text only, see http://msowww.anu.edu.au/~colless/Preprints/coma.html for text, tables and figures",
  "journal": "Astrophys.J.458:435,1996",
  "doi": "10.1086/176827",
  "categories": [
    "astro-ph"
  ],
  "abstract": "We examine the structure and dynamics of the galaxies in the Coma cluster using a catalog of 552 redshifts including 243 new measurements. The velocity distribution is shown to be non-Gaussian due to structure associated with the group of galaxies around NGC4839, 40 arcmin SW of the cluster core. We apply a mixture-modelling algorithm to the galaxy sample and obtain a robust partition into two subclusters which we use to examine the system's dynamics. We find that the late-type galaxies are freely-falling into a largely virialised cluster core dominated by early types. We obtain a virial mass for the main cluster in close agreement with the estimates derived from recent X-ray data. The mass of the NGC4839 group is about 5-10% the mass of the main cluster. Assuming the main cluster and the NGC4839 group follow a linear two-body orbit, the favored solution has the two clusters lying at 74 degrees to the line of sight at a true separation of 0.8 Mpc and moving together at 1700 km/s. The cluster core shows evidence of an ongoing merger between two subclusters centered in projection on the dominant galaxies NGC4874 and NGC4889 but offset in velocity by 300 km/s and 1100 km/s respectively. Combining these results with X-ray and radio observations, and an interpretation of the presence or lack of an extended halo around the dominant galaxies, we develop a merger history for the Coma cluster.",
  "revisions": [
    {
      "version": "v1",
      "updated": "1995-08-16T23:59:22.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "coma cluster",
      "main cluster",
      "virialised cluster core",
      "ngc4839 group",
      "linear two-body orbit"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 43,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 412804
    }
  }
}