37 GHz methanol masers : Horsemen of the Apocalypse for the class II methanol maser phase?

Abstract

We report the results of a search for class II methanol masers at 37.7, 38.3 and 38.5 GHz towards a sample of 70 high-mass star formation regions. We primarily searched towards regions known to show emission either from the 107 GHz class II methanol maser transition, or from the 6.035 GHz excited OH transition. We detected maser emission from 13 sources in the 37.7 GHz transition, eight of these being new detections. We detected maser emission from three sources in the 38 GHz transitions, one of which is a new detection. We find that 37.7 GHz methanol masers are only associated with the most luminous 6.7 and 12.2 GHz methanol maser sources, which in turn are hypothesised to be the oldest class II methanol sources. We suggest that the 37.7 GHz methanol masers are associated with a brief evolutionary phase (of 1000-4000 years) prior to the cessation of class II methanol maser activity in the associated high-mass star formation region.

14 pages, 4 figures, accepted for publication in ApJ

References in corpus (4)

• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• The H_2O southern Galactic Plane Survey (HOPS): I. Techniques and H_2O maser data
• Class I methanol masers in the outflow of IRAS 16547-4247
• Statistical properties of 12.2 GHz methanol masers associated with a complete sample of 6.7 GHz methanol masers

Cited by in corpus (26)

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• Trigonometric Parallaxes of Star Forming Regions in the Scutum Spiral Arm
• A Water Maser and Ammonia Survey of GLIMPSE Extended Green Objects (EGOs)
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• Detection of new methanol maser transitions associated with G358.93-0.03
• Discovery of six new class II methanol maser transitions, including the unambiguous detection of three torsionally excited lines toward G358.931-0.030
• A population of hypercompact HII regions identified from young HII regions
• First Parallax Measurements Towards a 6.7 GHz Methanol Maser with the Australian Long Baseline Array - Distance to G339.884-1.259
• Detection of 36 GHz class I methanol maser emission towards NGCS253
• 12.2-GHz methanol maser MMB follow-up catalogue - II. Longitude range 186 to 330 degrees
• Detection of a methanol megamaser in a major-merger galaxy
• A search for 95 GHz class I methanol masers in molecular outflows
• 84-GHz methanol masers, their relationship to 36-GHz methanol masers and their molecular environments
• 12.2-GHz methanol maser MMB follow-up catalogue - III. Longitude range 10 to 20 degrees
• Discovery of weak 6.7-GHz CH3OH masers in a sample of high-mass Hi-GAL sources
• Testing maser-based evolutionary schemes: A new search for 37.7-GHz methanol masers
• Modelling CH${}_3$OH masers: Sobolev approximation and accelerated lambda iteration method
• The 6-GHz multibeam maser survey III: comparison between the MMB and HOPS
• Discovery of Two New Class II Methanol Maser Transitions in G345.01+1.79
• The mid-infrared environments of 6.7 GHz Methanol Masers from the Methanol Multi-Beam Survey
• G10.472+0.027: An Extreme water maser outflow associated with a Massive Protostellar Cluster
• The first high-resolution observations of 19.9-GHz methanol masers
• Molecular line search toward the flaring 6.7-GHz methanol masers of G24.33+0.13 and G359.6-0.243: rare maser transitions detected
• Redshifted methanol absorption tracing infall motions of high-mass star formation regions
• A sensitive search for predicted methanol maser transitions with the Australia Telescope Compact Array
• Masers in star forming regions