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Millimetre wavelength methanol masers survey towards massive star forming regions

Published online by Cambridge University Press:  01 March 2007

T. Umemoto
Affiliation:
Nobeyama Radio Observatory, Minamimaki, Minamisaku, Nagano 384-1305, Japan email: umemoto@nro.nao.ac.jp
N. Mochizuki
Affiliation:
Institute of Space and Astronautical Science, Sagamihara, Kanagawa, 229-8510, Japan
K. M. Shibata
Affiliation:
National Astronomical Observatory, Mitaka, Tokyo 181-8588, Japan
D.-G. Roh
Affiliation:
Taeduk Radio Astronomy Observatory, Hwaam-Dong, Yusong-Gu, Daejon 305-348, Korea
H.-S. Chung
Affiliation:
Taeduk Radio Astronomy Observatory, Hwaam-Dong, Yusong-Gu, Daejon 305-348, Korea
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Abstract

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We present the results of a mm wavelength methanol maser survey towards massive star forming regions. We have carried out Class II methanol maser observations at 86.6 GHz, 86.9 GHz and 107.0 GHz, simultaneously, using the Nobeyama 45 m telescope. We selected 108 6.7 GHz methanol maser sources with declinations above −25 degrees and fluxes above 20 Jy. The detection limit of maser observations was ~3 Jy. Of the 93 sources surveyed so far, we detected methanol emission in 25 sources (27%) and “maser” emission in nine sources (10%), of which thre “maser” sources are new detections. The detection rate for maser emission is about half that of a survey of the southern sky (Caswell et al. 2000). There is a correlation between the maser flux of 107 GHz and 6.7 GHz/12 GHz emission, but no correlation with the “thermal” (non maser) emission. From results of other molecular line observations, we found that the sources with methanol emission show higher gas temperatures and twice the detection rate of SiO emission. This may suggest that dust evaporation and destruction by shock are responsible for the high abundance of methanol molecules, one of the required physical conditions for maser emission.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2008

References

Caswell, J. L., Yi, J., Booth, R. S. & Cragg, D. M. 2000, MNRAS, 313, 599CrossRefGoogle Scholar
Menten, K. M. 1991, ApJ (Letters) 380, L75CrossRefGoogle Scholar
Minier, V. & Booth, R. S. 2002, A&A, 387, 179Google Scholar
Szymczak, M., Hrynek, G. & Kuss, A. J. 2000, A&AS, 143, 269Google Scholar
Val'tts, I. E., Ellingsen, S. P., Slysh, V. I., kalenskii, S. V., Otrupcek, R. & Voronkov, M. A. 1999, MNRAS 310, 1077CrossRefGoogle Scholar