Production of 12.2 GHz CH3OH masers — Preliminary results of an excitation study

  • R. Peng
  • J. B. Whiteoak
8. Methanol Masers in Star Forming Regions
Part of the Lecture Notes in Physics book series (LNP, volume 412)


Excitation of the 20 → 3−1 E transition of CH3OH at 12.2 GHz has been examined in a statistical equilibrium study. The results show that mase emission can be produced in a molecular cloud with a bright HII region as immediate background. For cloud of kinetic temperature of 30 K, velocity gradient of 5 km 8−1 pc−1, H2 density of ≈ 105 cm−3 and methanol abundance of 10−6, and a continuum background of 50 K, the maser emission can reach a brightness temperature of ≈ 1300 K. This value would be much higher with smaller velocity gradient, where bright maser emission is usually expected.


Velocity Gradient Brightness Temperature Molecular Cloud Kinetic Temperature Maser Emission 
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Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • R. Peng
    • 1
  • J. B. Whiteoak
    • 2
  1. 1.Department of AstronomyUniversity of Illinois at Urbana-ChampaignUrbanaUSA
  2. 2.CSIRO Australia Telescope National FacilityEppingAustralia

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