{
  "id": "1707.07446",
  "version": "v1",
  "published": "2017-07-24T09:14:10.000Z",
  "updated": "2017-07-24T09:14:10.000Z",
  "title": "Detection of CH+, SH+, and their 13C- and 34S- isotopologues toward PKS1830-211",
  "authors": [
    "S. Muller",
    "H. S. P. M\"uller",
    "J. H. Black",
    "M. G'erin",
    "F. Combes",
    "S. Curran",
    "E. Falgarone",
    "M. Gu'elin",
    "C. Henkel",
    "S. Mart'in",
    "K. M. Menten",
    "E. Roueff",
    "S. Aalto",
    "A. Beelen",
    "T. Wiklind",
    "M. A. Zwaan"
  ],
  "comment": "accepted for publication in A&A",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "The z=0.89 molecular absorber toward PKS1830-211 provides us with the opportunity to probe the chemical and physical properties of the interstellar medium in the disk of a galaxy at a look-back time of half the present age of the Universe. Recent ALMA observations of hydrides have unveiled the multi-phase composition of this source's interstellar medium along two absorbing sightlines. Here, we report ALMA observations of CH+ and SH+, and of their 13C- and 34S- isotopologues, as potential tracers of energetic processes in the interstellar medium. CH+ and 13CH+ are detected toward both images of PKS1830-211, CH+ showing the deepest and broadest absorption among all species observed so far. The [CH+]/[13CH+] abundance ratio is ~100 in the south-west line of sight. [...] Toward the north-east image, we find an even larger value of [CH+]/[13CH+], 146 +/- 43, although with a large uncertainty. This sightline intercepts the absorber at a larger galactocentric radius than the southwestern one, where material might be less processed in stellar nucleosynthesis. In contrast to CH+ and its 13C isotopologue, SH+ and 34SH+ are only detected on the south-west sightline. These are the first detections of extragalactic SH+ and interstellar 34SH+. The spectroscopic parameters of SH+ are reevaluated and improved rest frequencies of 34SH+ are obtained. The [CH+]/[SH+] column density ratios show a large difference between the two lines of sight: ~25 and >600 toward the SW and NE image, respectively. We are not able to shed light on the formation process of CH+ and SH+ with these data, but the differences in the two sightlines toward PKS1830-211 suggest that their absorptions arise from gas with molecular fraction gtrsim 10%, with SH+ tracing significantly higher molecular fractions than CH+.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-07-24T09:14:10.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "isotopologue",
      "sources interstellar medium",
      "report alma observations",
      "larger galactocentric radius",
      "column density ratios"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}