Galactic Plane H2O Masers: A Southern Survey

Abstract

An extensive 22 GHz survey of H20 masers has been made with the Parkes 64 m radio telescope. We present data here for 68 sources, of which almost one-half were discovered in the present series of observations. The telescope beamsize, 100' arc to half-power, has enabled us to improve the position measurements of most of the known sources and in a few cases has allowed us to resolve a 'source' into several spatially separated components. The wide velocity coverage of our observations (> 200 km s -1) has led to the discovery of several interesting new high-velocity features. In addition to details for each source, the general properties of the sample are discussed. In the typical interval of 8 months between successive observations, the peak intensity of many sources varied only slightly (by less than a factor of 2); a few sources, however, showed more dramatic variations.