{
  "id": "2106.08835",
  "version": "v1",
  "published": "2021-06-16T14:53:33.000Z",
  "updated": "2021-06-16T14:53:33.000Z",
  "title": "AT2019 avd: A tidal disruption event with a two-phase evolution",
  "authors": [
    "Jin-Hong Chen",
    "Li-Ming Dou",
    "Rong-Feng Shen"
  ],
  "comment": "14 pages, 11 figures, 4 tables, Submitted to ApJ",
  "categories": [
    "astro-ph.HE",
    "astro-ph.GA"
  ],
  "abstract": "Tidal disruption events (TDEs) can uncover the quiescent super-massive black holes (SMBHs) at the center of galaxies and also offer a promising method to study them. After the disruption of a star by a SMBH, the highly elliptical orbit of the debris stream will be gradually circularized due to the self-crossing, and then the circularized debris will form an accretion disk. The recent TDE candidate AT 2019avd has double peaks in its optical light curve, and the X-ray emerges near the second peak. The durations of the peaks are about 400 and 600 days, respectively, and the separation between them is ~ 700 days. We fit and analyse its spectral energy distribution (SED) in optical/UV, mid-infrared, and X-ray bands. We find that this source can be interpreted as the circularization process in the first phase plus the delayed accretion process in the second phase. Under this two-phase scenario, we use the succession of self-crossing circularization model to fit the first peak, and the delayed accretion model to fit the second peak. The fitting results are consistent with the partial disruption of a 0.9 M_sun star by a 7 * 10^6 M_sun SMBH with the penetration factor \\beta ~ 0.6. Furthermore, we find the large-amplitude (by factors up to ~ 5) X-ray variability in AT 2019avd can be interpreted as the rigid-body precession of the misaligned disk due to the Lense-Thirring effect of a spinning SMBH, with the disk precession period of 10 - 25 days.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-06-16T14:53:33.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "tidal disruption event",
      "at2019 avd",
      "two-phase evolution",
      "second peak",
      "disk precession period"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 14,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}