{
  "id": "2006.02234",
  "version": "v1",
  "published": "2020-06-01T18:43:28.000Z",
  "updated": "2020-06-01T18:43:28.000Z",
  "title": "H$α$ Luminosity of ATLAS18qtd Does Not Plateau in the Nebular Phase",
  "authors": [
    "Michael A. Tucker",
    "Benjamin J. Shappee"
  ],
  "comment": "AAS Research Note. 4 pages, 1 figure",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We present new spectroscopic and photometric observations of ATLAS18qtd/SN 2018cqj, a fast-declining Type Ia supernova with variable H$\\alpha$ emission in previously-published nebular phase spectra. ATLAS18qtd is undetected in both spectroscopic and photometric observations which occurred at $\\sim 540~\\rm d$ after maximum light and $\\sim 230~\\rm d$ after the last H$\\alpha$ detection. With these new non-detections, we place an upper limit on the H$\\alpha$ luminosity of $\\lesssim 1.1\\times 10^{36}~\\rm{erg}~\\rm s^{-1}$ indicating the H$\\alpha$ flux decreased by a factor of $\\gtrsim 4$ since the previous detection. This upper limit excludes H$\\alpha$ emission that plateaus or increases since the previous detection but cannot confirm that the H$\\alpha$ emission decay rate is equivalent to the supernova decay rate.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-06-01T18:43:28.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "luminosity",
      "atlas18qtd",
      "photometric observations",
      "upper limit excludes",
      "emission decay rate"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 4,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}