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VLA Observations of Class I Methanol Masers in the Region of Low-Mass Star Formation L1157

S. V. Kalenskii ; S. Kurtz ; V. I. Slysh ; P. Hofner ; C. M. Walmsley ; Lars E.B. Johansson (Institutionen för radio- och rymdvetenskap, Nationella anläggningen för radioastronomi) ; Per Bergman (Institutionen för radio- och rymdvetenskap, Nationella anläggningen för radioastronomi)
Astronomy Reports (1063-7729). Vol. 54 (2010), 10, p. 932-939.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: 1157 molecular outflow, line, ghz



Denna post skapades 2010-11-12. Senast ändrad 2014-09-02.
CPL Pubid: 129017

 

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Institutioner (Chalmers)

Institutionen för radio- och rymdvetenskap, Nationella anläggningen för radioastronomi (2005-2010)

Ämnesområden

Astronomi, astrofysik och kosmologi

Chalmers infrastruktur