Excitation of the 51 - 60 A+ Methanol Transition

Details Excitation of the 51 - 60 A+ Methanol Transition Excitation of the 51 - 60 A+ Methanol Transition

Jan 2009

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009aas...21336001k&link_type=abstract

American Astronomical Society, AAS Meeting #213, #360.01; Bulletin of the American Astronomical Society, Vol. 41, p.509

Astronomy and Astrophysics

Astronomy

Scientific paper

We are conducting an investigation of the excitation of the 6.7 GHz methanol maser line to determine the physical conditions that produce the inversion in this strongest of methanol masers. We have observed the ΔJ = -1, ΔK = 0 transitions at 290.1, 287.7 and 239.7 GHz, which connect to the levels of the maser line, towards a sample of strong Class II masers. The observations of the 51-41 A+ line at 239.7 GHz and 60-50 A+ line at 290.1 GHz make it possible to determine the relative populations (excitation temperature) of the 6.7 GHz maser levels. The derived excitation temperatures for the maser line, averaged over the 30" CSO beam, are in most cases positive. The lack of inversion suggests that the beam averages over regions with quasi-thermal and maser emission and that the regions which are inverted are much smaller than the CSO beam. A map of the W51 region in thermal methanol lines shows that the strongest masers occur at or near the peak of thermal methanol emission which indicates a correlation between methanol column density and maser intensity. We plan also to map the Orion OMC-1 region, where the mm emission is intense but the 6.7 GHz emission fairly weak and, interestingly, extended. The DR21 region also has mm emission strong enough to be mapped in reasonable time.
Our colleague and friend Slava Slysh passed away in September. We miss his inspiring insights and dedicate this work to his memory.
The work by TBHK and PFG was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration.

Affiliated with

Also associated with

No associations

Rating

Excitation of the 51 - 60 A+ Methanol Transition does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Excitation of the 51 - 60 A+ Methanol Transition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Excitation of the 51 - 60 A+ Methanol Transition will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1700779