{
  "id": "1710.03371",
  "version": "v1",
  "published": "2017-10-10T01:26:48.000Z",
  "updated": "2017-10-10T01:26:48.000Z",
  "title": "Discovery of the new X-ray transient MAXI J1807+132: a Candidate of a Neutron Star Low-mass X-ray binary",
  "authors": [
    "Megumi Shidatsu",
    "Yutaro Tachibana",
    "Taketoshi Yoshii",
    "Hitoshi Negoro",
    "Taiki Kawamuro",
    "Wataru Iwakiri",
    "Satoshi Nakahira",
    "Kazuo Makishima",
    "Yoshihiro Ueda",
    "Nobuyuki Kawai",
    "Motoko Serino",
    "Jamie Kennea"
  ],
  "comment": "13 pages, 11 figures, accepted for publication in ApJ",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "We report on the detection and follow-up multi-wavelength observations of the new X-ray transient MAXI J1807+132 with the MAXI/GSC, Swift, and ground-based optical telescopes. The source was first recognized with the MAXI/GSC on 2017 March 13. About a week later, it reached the maximum intensity ($\\sim$10 mCrab in 2-10 keV), and then gradually faded in $\\sim$10 days by more than one order of magnitude. Time-averaged Swift/XRT spectra in the decaying phase can be described by a blackbody with a relatively low temperature (0.1-0.5 keV), plus a hard power-law component with a photon index of $\\sim$2. These spectral properties are similar to those of neutron star low-mass X-ray binaries (LMXBs) in their dim periods. The blackbody temperature and the radius of the emission region varied in a complex manner as the source became dimmer. The source was detected in the optical wavelength on March 27-31 as well. The optical flux decreased monotonically as the X-ray flux decayed. The correlation between the X-ray and optical fluxes is found to be consistent with those of known neutron star LMXBs, supporting the idea that the source is likely to be a transient neutron star LMXB.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-10-10T01:26:48.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "neutron star low-mass x-ray binary",
      "x-ray transient maxi",
      "transient neutron star lmxb"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 13,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}