Maser radiometer observations of water vapor and OH in weak galactic OH sources

Abstract

Observations of water vapor and ground-state hydroxyl lines in weak galactic OH sources were performed with maser-equipped radio telescopes at the NEROC Haystack Observatory and Onsala Space Observatory, Sweden, respectively. In general, the weak sources exhibit simpler spectra than the strong sources, and detailed correlation studies are facilitated. New water vapor sources have been detected in W37, W43 N, NGC 2438, and ON-3. W12 and W37 are examples of sources in which H2O masses while OH is seen only in absorption. In other sources, e.g., W31 and W43 N, the velocities of H2O and OH correlate well. Interferometer measurements of the positions of these fairly weak H2O sources are required for further correlation between OH and H2O.