{
  "id": "2109.11123",
  "version": "v1",
  "published": "2021-09-23T03:28:49.000Z",
  "updated": "2021-09-23T03:28:49.000Z",
  "title": "The detection of a hot molecular core in the extreme outer Galaxy",
  "authors": [
    "Takashi Shimonishi",
    "Natsuko Izumi",
    "Kenji Furuya",
    "Chikako Yasui"
  ],
  "comment": "Accepted for publication in ApJ, 44 pages, 24 figures, 13 tables",
  "categories": [
    "astro-ph.GA",
    "astro-ph.EP",
    "astro-ph.SR"
  ],
  "abstract": "Interstellar chemistry in low metallicity environments is crucial to understand chemical processes in the past metal-poor universe. Recent studies of interstellar molecules in nearby low-metallicity galaxies have suggested that the metallicity has a significant effect on chemistry of star-forming cores. Here we report the first detection of a hot molecular core in the extreme outer Galaxy, which is an excellent laboratory to study star formation and interstellar medium in a Galactic low-metallicity environment. The target star-forming region, WB89-789, is located at the galactocentric distance of 19 kpc. Our ALMA observations in 241-246, 256-261, 337-341, and 349-353 GHz have detected a variety of carbon-, oxygen-, nitrogen-, sulfur-, and silicon-bearing species, including complex organic molecules (COMs) containing up to nine atoms, towards a warm (>100 K) and compact (<0.03 pc) region associated with a protostar (~8x10^3 L_sun). Deuterated species such as HDO, HDCO, D2CO, and CH2DOH are also detected. A comparison of fractional abundances of COMs relative to CH3OH between the outer Galactic hot core and an inner Galactic counterpart shows a remarkable similarity. On the other hand, the molecular abundances in the present source do not resemble those of low-metallicity hot cores in the Large Magellanic Cloud. The results suggest that a great molecular complexity exists even in a primordial environment of the extreme outer Galaxy. The detection of another embedded protostar associated with high-velocity SiO outflows is also reported.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-09-23T03:28:49.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "extreme outer galaxy",
      "hot molecular core",
      "outer galactic hot core",
      "high-velocity sio outflows",
      "interstellar"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 44,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}