Introduction

The dust and high stellar density of the Milky Way obscures up to 25% of the optical extragalactic sky, creating a Zone of Avoidance (ZOA). The resulting incomplete coverage of surveys of external galaxies leaves open the possibility that dynamically important structures, or even nearby massive galaxies, remain undiscovered. Careful searches in the optical and infrared wave bands can narrow the ZOA, (see Kraan-Korteweg, this volume) but in the regions of highest obscuration and infrared confusion, only radio surveys can find galaxies. The 21 cm line of neutral hydrogen (HI) passes readily through the obscuration, so galaxies with sufficient HI can be found through detection of their 21 cm emission. Of course, this method will miss HI-poor, early-type galaxies, and cannot discriminate HI galaxies with redshifts near zero velocity from Galactic HI.

Here we describe an HI blind survey for galaxies in the southern ZOA conducted with the new multibeam receiver on the 64-m Parkes telescope. A survey of HI galaxies in the northern ZOA is underway with the Dwingeloo radiotelescope (Henning et al. 1998; Rivers et al. this volume).

© Copyright Astronomical Society of Australia 1997