First interstellar HCO+ maser

Nicholas S. Hakobian, Richard M. Crutcher

Research output: Contribution to journalArticlepeer-review


A previously unseen maser in the J = 1-0 transition of HCO+ has been detected by the Combined Array for Millimeter-wave Astronomy (CARMA). A subarcsecond map was produced of the 2arcmin2 region around DR21(OH), which has had previous detections of OH and methanol masers. This new object has remained undetected until now due to its extremely compact size. The object has a brightness temperature of >2500K and an FWHM linewidth of 0.497kms -1, both of which suggest non-thermal line emission consistent with an unsaturated maser. This object coincides in position and velocity with the methanol maser named DR21(OH)-1 by Plambeck & Menten. No compact HCO + emission was present in the CARMA data toward the other methanol masers described in that Letter. These new results support the theory introduced in Plambeck & Menten that these masers likely arise from strong outflows interacting with low mass, high density pockets of molecular gas. This is further supported by recent observations of a CO outflow by Zapata etal. that traces the outflow edges and confirms that the maser position lies along the edge of the outflow where interaction with molecular tracers can occur.

Original languageEnglish (US)
Article numberL18
JournalAstrophysical Journal Letters
Issue number1
StatePublished - Oct 10 2012

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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