Search

Twenty-four bright, steep-spectrum far-infrared IRAS point sources, which were originally discussed by Hughes & MacLeod, have been searched for hydroxyl, water, and methanol masers and for formaldehyde absorption features. Distances and spectral types for the stars exciting these masers were estimated using radio continuum, IRAS spectra, and maser velocity data. It is found that 21 of the 24 sources are regions of massive star formation containing stars earlier than type B2. We report the discovery of five new OH masers, one new 6.7 GHz CH3OH maser, and two new 12.2 GHz CH3OH masers toward these IRAS sources. By contrast, no 4.765 GHz excited-OH masers were found toward these sources. This sample contains only star-forming regions; there are no planetary or reflection nebulae or extragalactic sources present, as seen in samples with less extreme IRAS colors.

Observations of water vapor and silicon monoxide masers were conducted in the direction of G305.8−0.2. No SiO maser emission above 7 Jy of flux density was detected. The short-time variability of the H 2 O maser together with the absence of compact radio continuum emission suggests that the excitation energy of the maser could originate from an O7-O9 protostar in its earlier evolutionary stages

Microwave emission associated with the para form of ammonia, in the (1, 1) line, was searched for in the direction of 46 southern sky positions where strong H/sub 2/CO absorption or strong H/sub 2/O maser emission was observed previously. The results of those observations are presented with 17 new ammonia sources discovered.

An extensive search for water vapor maser emission towards the Large and Small Magellanic Clouds is reported. The 6/sub 16/--5/sub 23/ transition of water molecule was detected in two H II regions in LMC (including N 159, previously was detected) and in two H II regions in SMC. A total of 32 positions was searched in both Clouds. The strength of the sources detected is comparable with galactic masers with luminosities L< or approx. =10/sup -2/L/sub sun/.