{
  "id": "1706.02446",
  "version": "v1",
  "published": "2017-06-08T03:33:52.000Z",
  "updated": "2017-06-08T03:33:52.000Z",
  "title": "SiS in the circumstellar envelope of IRC +10126: maser and quasi-thermal emission",
  "authors": [
    "Y. Gong",
    "C. Henkel",
    "J. Ott",
    "K. M. Menten",
    "M. R. Morris",
    "D. Keller",
    "M. J. Claussen",
    "M. Grasshoff",
    "R. Q. Mao"
  ],
  "comment": "Accepted for publication in ApJ. A high-resolution version can be found at https://gongyan2444.github.io/pdf/cw-leo-sis.pdf 3D movies of SiS cubes can be found at https://gongyan2444.github.io/movie/sis10-3d.avi and https://gongyan2444.github.io/movie/sis21-3d.avi",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "We present new Effelsberg-100 m, ATCA, and VLA observations of rotational SiS transitions in the circumstellar envelope (CSE) of IRC +10216. Thanks to the high angular resolution achieved by the ATCA observations, we unambiguously confirm that the molecule's J=1-0 transition exhibits maser action in this CSE, as first suggested more than thirty years ago. The maser emission's radial velocity peaking at a local standard of rest velocity of -39.862$\\pm$0.065 km/s indicates that it arises from an almost fully accelerated shell. Monitoring observations show time variability of the SiS (1-0) maser. The two lowest-$J$ SiS quasi-thermal emission lines trace a much more extended emitting region than previous high-J SiS observations. Their distributions show that the SiS quasi-thermal emission consists of two components: one is very compact (radius<1.5\", corresponding to <3$\\times 10^{15}$ cm), and the other extends out to a radius >11\". An incomplete shell-like structure is found in the north-east, which is indicative of existing SiS shells. Clumpy structures are also revealed in this CSE. The gain of the SiS (1-0) maser (optical depths of about -5 at the blue-shifted side and, assuming inversion throughout the entire line's velocity range, about -2 at the red-shifted side) suggests that it is unsaturated. The SiS (1-0) maser can be explained in terms of ro-vibrational excitation caused by infrared pumping, and we propose that infrared continuum emission is the main pumping source.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-06-08T03:33:52.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "circumstellar envelope",
      "emissions radial velocity peaking",
      "sis quasi-thermal emission lines trace",
      "maser emissions radial velocity",
      "observations"
    ],
    "tags": [
      "github project"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}