VLA Observations of Class I Methanol Masers in the Region of Low-Mass Star Formation L1157
Journal article, 2010
We present the results of VLA observations of a maser candidate in the low-mass star formation region L1157 in the 7(0)-6(1) A(+) transition at 44 GHz. The line is emitted by a compact, undoubtedly maser source associated with clump B0a, which is seen in maps of L1157 in thermal lines of methanol and other molecules. A much weaker compact source is associated with clump B1a, which is brighter than B0a in thermal methanol lines. The newly detected masers may form in thin layers of turbulent post-shock gas. In this case, the maser emission may be beamed, so that only an observer located in or near the planes of the layers can observe strong masers. On the other hand, the maser lines are double with a "red" asymmetry, indicating that the masers may form in collapsing clumps. A detailed analysis of collapsing-cloud maser models and their applicability to the masers in L1157 will be developed in subsequent papers.
line
ghz
1157 molecular outflow
Author
S. V. Kalenskii
Pn Lebedev Physics Institute, Russian Academy of Sciences
S. Kurtz
Universidad Nacional Autonoma de Mexico
V. I. Slysh
Pn Lebedev Physics Institute, Russian Academy of Sciences
P. Hofner
National Radio Astronomy Observatory Socorro
New Mexico Inst of Mining and
Max Planck Institut fur Radioastronomie
C. M. Walmsley
Osservatorio Astrofisico Di Arcetri
Lars E B Johansson
Chalmers, Department of Radio and Space Science, National Facility for Radio Astronomy
Per Bergman
Chalmers, Department of Radio and Space Science, National Facility for Radio Astronomy
Astronomy Reports
1063-7729 (ISSN) 1562-6881 (eISSN)
Vol. 54 10 932-939Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1134/S1063772910100069