{
  "id": "astro-ph/0007406",
  "version": "v2",
  "published": "2000-07-26T20:28:49.000Z",
  "updated": "2000-09-29T20:09:42.000Z",
  "title": "The Discovery of Broad P Cygni X-ray Lines from Circinus X-1 with the Chandra High Energy Transmission Grating Spectrometer",
  "authors": [
    "W. N. Brandt",
    "N. S. Schulz"
  ],
  "comment": "17 pages, ApJL, in press; minor improvements made to address referee's suggestions",
  "doi": "10.1086/317313",
  "categories": [
    "astro-ph"
  ],
  "abstract": "We present the first grating-resolution X-ray spectra of the X-ray binary Cir X-1, obtained with the High Energy Transmission Grating Spectrometer on Chandra. These reveal a rich set of lines from H-like and/or He-like Ne, Mg, Si, S and Fe detected with a high signal-to-noise ratio. The lines are broad (+/- 2000 km/s) and show P Cygni profiles. The absorption components of the lines extend to low velocity, and they have about the same widths and strengths as the corresponding emission components. The widths of the X-ray P Cygni lines are comparable to that of the broad component of the strong, asymmetric H-alpha line from Cir X-1, suggesting that the two phenomena may be related. We discuss outflow models and propose that the P Cygni profiles may arise in the moderate temperature (5 x 10^6 K) region of the wind from an X-ray heated accretion disk. This basic picture strengthens the idea that the accretion disk in Cir X-1 is viewed in a relatively edge-on manner, and it suggests that Cir X-1 is the X-ray binary analog of a Broad Absorption Line quasar.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2000-09-29T20:09:42.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "high energy transmission grating spectrometer",
      "chandra high energy transmission grating",
      "cygni x-ray lines"
    ],
    "tags": [
      "journal article"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 546855
    }
  }
}