A large-scale spectroscopic survey of methanol and oh line emission from the galactic center: Observations and data

W. D. Cotton, F. Yusef-Zadeh

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Class I methanol masers are collisionally pumped and are generally correlated with outflows in star-forming sites in the Galaxy. Using the Very Large Array in its A-array configuration, we present a spectral line survey to identify methanol J=4-1 → 30E emission at 36.169 GHz. Over 900 pointings were used to cover a region 66′×13′ along the inner Galactic plane. A shallow survey of OH at 1612, 1665, 1667, and 1720 MHz was also carried out over the area covered by our methanol survey. We provide a catalog of 2240 methanol masers with narrow linewidths of ∼1 km s-1, spatial resolutions of ∼0″.14 × 0″.05, and rms noises ∼20 mJy beam-1 per channel. Lower limits on the brightness temperature range from 27,000 to 10,000,000 K, showing that the emission is of nonthermal origin. We also provide a list of 23 OH (1612), 14 OH (1665), 5 OH (1667), and 5 OH (1720 MHz) masers. The origin of such a large number of methanol masers is not clear. Many methanol masers appear to be associated with infrared dark clouds, though it appears unlikely that the entire population of these masers traces the early phase of star formation in the Galactic center.

Original languageEnglish (US)
Article number10
JournalAstrophysical Journal, Supplement Series
Volume227
Issue number1
DOIs
StatePublished - Nov 2016

Keywords

  • Galaxy: center
  • ISM: clouds
  • ISM: molecules
  • ISM: structure

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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