SHOCK-EXCITED MASER EMISSION FROM SUPERNOVA-REMNANTS - G32.8-0.1, G337.8-0.1 G346.6-0.2, AND THE HB 3 W3 COMPLEX/

We present the results of VLA observations in the ground-state hydroxy l (OH) transition at 1720 MHz toward 20 supernova remnants (SNRs). We detect compact emission 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 re sults from masers that are shock-excited due to the interaction of the SNR and an adjacent molecular cloud. We observe a characteristic Zeem an profile in the Stokes V spectrum, which allows us to derive a magne tic field of 1.5 and 1.7 mG for G32.8-0.1 and G346.6-0.2, respectively . The velocity of the masers also allows us to determine a kinematic d istance to the supernova remnants (SNRs). Our criteria for a maser to be associated with an SNR along the line of sight are that the positio n and velocity of the maser and SNR must agree and the OH (1720) emiss ion must be unaccompanied by other OH lines.