{
  "id": "2007.09487",
  "version": "v1",
  "published": "2020-07-18T17:45:06.000Z",
  "updated": "2020-07-18T17:45:06.000Z",
  "title": "Identification of a New Ultraluminous X-ray Source in NGC 1316",
  "authors": [
    "S. Allak",
    "A. Akyuz",
    "N. Aksaker",
    "M. Ozdogan Ela",
    "S. Avdan",
    "F. Soydugan"
  ],
  "categories": [
    "astro-ph.HE",
    "astro-ph.GA",
    "astro-ph.SR"
  ],
  "abstract": "In this study, we report identification of a new ultraluminous X-ray source (ULX) which we named as X-7 in NGC 1316, with an unabsorbed luminosity of 2.10$\\times$10$^{39}$ erg s$^{-1}$ using two recent {\\it Chandra} archival observations. The X-7 was detected in the {\\it Chandra} 2001 observation and it was included in the X-ray source list of the NGC 1316 as CXOUJ032240.8-371224 with luminosity of 5.7$\\times$10$^{38}$ erg s$^{-1}$ implying a luminosity increase of a factor of $\\sim$ 4. The best fit spectral model parameters indicate that X-7 has a relatively hot disk and hard spectra. The mass of compact object is obtained as $\\sim$ 8 M$\\odot$ which is in the range of a stellar-mass black hole. The X-7 shows a relatively long-term count rate variability while no short-term variability is observed. We also identified a unique optical candidate within $0.\\arcsec22$ error circle at 95\\% confidence level for X-7 using the archival {\\it HST}/ACS and {\\it HST}/WFC3 data. Absolute magnitude (M$_{V}$) of this candidate is -7.8 mag. Its spectral energy distribution is adequately fitted a blackbody model with a temperature of 3100 K indicating an M type supergiant, assuming the donor star dominates the optical emission. In addition, we identified a transient ULX candidate (XT-1) has a high luminosity of $\\sim$ 10$^{39}$ erg s$^{-1}$ located 6 $\\arcsec$ away from X-7 with no visible counterpart(s).",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-07-18T17:45:06.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "ultraluminous x-ray source",
      "best fit spectral model parameters",
      "identification",
      "relatively long-term count rate variability",
      "luminosity"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}