Open AccessShock-excited Maser Emission from Supernova Remnants: G32.8−0.1, G337.8−0.1, G346.6−0.2, and the HB 3/W3 Complex
Author(s) -
Barron Koralesky,
D. A. Frail,
W. M. Goss,
M. J. Claussen,
A. J. Green
Publication year - 1998
Publication title -
the astronomical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.61
H-Index - 271
eISSN - 1538-3881
pISSN - 0004-6256
DOI - 10.1086/300508
Subject(s) - maser , physics , astrophysics , excited state , supernova , zeeman effect , supernova remnant , shock (circulatory) , molecular cloud , line (geometry) , line of sight , emission spectrum , astronomy , atomic physics , magnetic field , spectral line , stars , quantum mechanics , medicine , geometry , mathematics
We present the results of VLA observations in the ground-state hydroxyl (OH)transition at 1720 MHz toward 20 supernova remnants (SNRs). We detect compactemission from four objects. For three of these objects (G32.8-0.1, G337.8-0.1,and G346.6-0.2), we argue that the emission results from masers which areshock-excited due to the interaction of the SNR and an adjacent molecularcloud. We observe a characteristic Zeeman profile in the Stokes V spectrum,which allows us to derive a magnetic field of 1.5 and 1.7 mG for G32.8-0.1 andG346.6-0.2, respectively. The velocity of the masers also allows us todetermine a kinematic distance to the SNR. Our criteria for a maser to beassociated with an SNR along the line of sight are that the position andvelocity of the maser and SNR must agree, and the OH(1720) emission must beunaccompanied by other OH lines.Comment: Accepted to the Astronomical Journal (19 pages total, 6 figures, 4 tables
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