{
  "id": "1701.01364",
  "version": "v1",
  "published": "2017-01-05T16:07:55.000Z",
  "updated": "2017-01-05T16:07:55.000Z",
  "title": "Occurrence of radio minihalos in a mass-limited sample of galaxy clusters",
  "authors": [
    "Simona Giacintucci",
    "Maxim Markevitch",
    "Rossella Cassano",
    "Tiziana Venturi",
    "Tracy E. Clarke",
    "Gianfranco Brunetti"
  ],
  "comment": "29 pages, 11 figures, 9 tables. Submitted to ApJ",
  "categories": [
    "astro-ph.HE",
    "astro-ph.CO"
  ],
  "abstract": "We investigate the occurrence of radio minihalos - diffuse radio sources of unknown origin observed in the cores of some galaxy clusters - in a statistical sample of 58 clusters drawn from the Planck Sunyaev-Zel'dovich cluster catalog using a mass cut ($M_{500}>6\\times 10^{14} \\, M_{\\odot}$). We supplement our statistical sample with a similarly-sized non-statistical sample mostly consisting of clusters in the ACCEPT X-ray catalog with suitable X-ray and radio data. Where necessary, we reanalyzed the Very Large Array archival radio data to determine if a mihinalo is present. Our total sample includes all 28 currently known and recently discovered radio minihalos, including 6 candidates. We classify clusters as cool-core or non-cool core according to the value of the specific entropy floor in the cluster center, rederived or newly derived from the Chandra X-ray density and temperature profiles where necessary (for 26 clusters). Contrary to the common wisdom that minihalos are rare, we find that almost all cool cores - at least 12 out of 15 (80%) - in our complete sample of massive clusters exhibit minihalos. The supplementary sample, which includes clusters with lower total masses, shows that the occurrence of minihalos may be lower in lower-mass cool-core clusters. No minihalos are found in non-cool-cores or \"warm cores\". These findings encode information on the origin of minihalos and provide information on the physical processes and energetics of the cluster cores.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-01-05T16:07:55.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "radio minihalos",
      "galaxy clusters",
      "mass-limited sample",
      "occurrence",
      "large array archival radio data"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 29,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}