{
  "id": "2308.09459",
  "version": "v1",
  "published": "2023-08-18T10:46:25.000Z",
  "updated": "2023-08-18T10:46:25.000Z",
  "title": "The first detection of SiC$_2$ in the interstellar medium",
  "authors": [
    "S. Massalkhi",
    "I. Jiménez-Serra",
    "J. Martín-Pintado",
    "V. M. Rivilla",
    "L. Colzi",
    "S. Zeng",
    "S. Martín",
    "B. Tercero",
    "P. de Vicente",
    "M. A. Requena-Torres"
  ],
  "comment": "8 pages, 5 figures",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We report the first detection of SiC$_2$ in the interstellar medium. The molecule was identified through six rotational transitions toward G\\,+0.693$-$0.027, a molecular cloud located in the Galactic center. The detection is based on a line survey carried out with the GBT, the Yebes 40m, and the IRAM 30m telescopes covering a range of frequencies from 12 to 276 GHz. We fit the observed spectra assuming local thermodynamic equilibrium and derive a column density of ($1.02\\pm0.04)\\times10^{13}$ cm$^{-2}$, which gives a fractional abundance of $7.5\\times10^{-11}$ with respect to H$_2$, and an excitation temperature of $5.9\\pm0.2$ K. We conclude that SiC$_2$ can be formed in the shocked gas by a reaction between the sputtered atomic silicon and C$_2$H$_2$, or it can be released directly from the dust grains due to disruption. We also search for other Si-bearing molecules and detect eight rotational transitions of SiS and four transitions of Si$^{18}$O. The derived fractional abundances are $3.9\\times10^{-10}$ and $2.1\\times10^{-11}$, respectively. All Si-bearing species toward G\\,+0.693$-$0.027 show fractional abundances well below what is typically found in late-type evolved stars.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2023-08-18T10:46:25.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "interstellar medium",
      "first detection",
      "fractional abundance",
      "rotational transitions",
      "spectra assuming local thermodynamic equilibrium"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 8,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}