{
  "id": "1110.2238",
  "version": "v2",
  "published": "2011-10-11T00:36:13.000Z",
  "updated": "2011-10-26T00:54:18.000Z",
  "title": "New Maser Emission from Nonmetastable Ammonia in NGC 7538. II. Green Bank Telescope Observations Including Water Masers",
  "authors": [
    "Ian M. Hoffman",
    "Stella Seojin Kim"
  ],
  "comment": "7 pages, 4 figures, 3 tables; accepted to AJ; color figures only on arxiv; revised to include references and minor proof changes",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present new maser emission from ^{14}NH_3 (9,6) in NGC 7538. Our observations include the known spectral features near v_LSR = -60 km/s and -57 km/s and several more features extending to -46 km/s. In three epochs of observation spanning two months we do not detect any variability in the ammonia masers, in contrast to the >10-fold variability observed in other ^{14}NH_3 (9,6) masers in the Galaxy over comparable timescales. We also present observations of water masers in all three epochs for which emission is observed over the velocity range -105 km/s < v_LSR < -4 km/s, including the highest velocity water emission yet observed from NGC 7538. Of the remarkable number of maser species in IRS 1, H_2O and, now, ^{14}NH_3 are the only masers known to exhibit emission outside of the velocity range -62 km/s < v_LSR < -51 km/s. However, we find no significant intensity or velocity correlations between the water emission and ammonia emission. We also present a non-detection in the most sensitive search to date toward any source for emission from the CC^{32}S and CC^{34}S molecules, indicating an age greater than \\approx 10^4 yr for IRS 1-3. We discuss these findings in the context of embedded stellar cores and recent models of the region.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2011-10-26T00:54:18.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "green bank telescope observations",
      "maser emission",
      "water masers",
      "nonmetastable ammonia",
      "velocity range"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-6256/142/6/202",
      "journal": "The Astronomical Journal",
      "year": 2011,
      "month": "Dec",
      "volume": 142,
      "number": 6,
      "pages": 202
    },
    "note": {
      "typesetting": "TeX",
      "pages": 7,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 939776,
      "adsabs": "2011AJ....142..202H"
    }
  }
}