{
  "id": "2007.12093",
  "version": "v1",
  "published": "2020-07-23T15:55:43.000Z",
  "updated": "2020-07-23T15:55:43.000Z",
  "title": "VLA Limits on Intermediate-Mass Black Holes in 19 Massive Globular Clusters",
  "authors": [
    "J. M. Wrobel",
    "K. E. Nyland"
  ],
  "comment": "8 pages, 4 figures, accepted 2020 July 22 by ApJ",
  "categories": [
    "astro-ph.GA",
    "astro-ph.HE"
  ],
  "abstract": "The NSF's Karl G.\\ Jansky Very Large Array (VLA) was used at 3~cm to search for accretion signatures from intermediate-mass black holes (IMBHs) in 19 globular star clusters (GCs) in NGC\\,3115, an early-type galaxy at a distance of 9.4 Mpc. The 19 have stellar masses $M_{\\star} \\sim (1.1 - 2.7) \\times 10^6~M_\\odot$, with a mean $\\overline{M_{\\star}} \\sim 1.8 \\times 10^6~M_\\odot$. None were detected. An IMBH accretion model was applied to the individual GCs and their radio stack. The radio-stacked GCs have an IMBH mass $\\overline{M_{\\rm IMBH}} < 1.7 \\times 10^5~M_\\odot$ and mass fraction $\\overline{M_{\\rm IMBH}} / \\overline{M_{\\star}} < 9.5\\%$, with each limit being uncertain by a factor of about 2.5. The latter limit contrasts with the extremes of some stripped nuclei, suggesting that the set of stacked GCs in NGC\\,3115 is not a set of such nuclei. The radio luminosities of the individual GCs correspond to X-ray luminosities $L_{\\rm X} < (3.3 - 10) \\times 10^{38}$ erg~s$^{-1}$, with a factor of about 2.5 uncertainty. These limits predicted for putative IMBHs in the GCs are consistent with extant {\\em Chandra} observations. Finally, a simulated observation with a next-generation VLA (ngVLA) demonstrates that accretion signatures from IMBHs in GCs can be detected in a radio-only search, yet elude detection in an X-ray-only search due to confusion from X-ray binaries in the GCs.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-07-23T15:55:43.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "intermediate-mass black holes",
      "massive globular clusters",
      "vla limits",
      "accretion signatures",
      "globular star clusters"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 8,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}