An ISO survey of possible water and hydroxyl IRASER transitions towards the star-forming regions W49, W3(OH) and Sgr B2M

Abstract

We report ISO LWS observations towards the star-forming regions W49N, W3(OH) and Sgr B2M in LWS04 mode (high-resolution Fabry-Perot scans). Possible far-infrared laser emission was detected in a water line at 133.55μm towards W49N, but the spectral resolution was inadequate to establish firmly the nature of the emission. An additional water line was marginally detected in absorption at the 3σ level, also towards W49N, at 169.74μm. No OH lines were detected towards Sgr B2M or W3(OH) at either 134.83 or 135.95μm, either in emission or in absorption.