Bright prospects: Comparing the Hα survey with large-scale radio continuum emission

Abstract

Prospects for comparisons between the AAO/UKST Hα survey and large-scale radio continuum emission are considered, with particular reference to the recently completed Parkes 2-4 GHz survey of the southern Galactic Plane. Both these surveys have a high sensitivity to thermal emission, and comparisons between the Parkes work and previous Hα surveys show many objects in common. Possibilities for new detections include: a number of new supernova remnants; the faint extensions and envelopes surrounding 'classical' H II complexes, and other faint regions of thermal emission; several active H II complexes, including an outflow of ionised gas from IC 4628 and a number of bi-polar 'plumes' of low-density, thermal material apparently associated with H II complexes on the Carina spiral arm.