A UKST H survey of the Galactic plane

The Scientific Aims and details of the Survey

H emission lines from HII regions are one of the most direct optical tracers of current star formation activity. These lines also trace out the distribution of ionized gas in the ISM in general revealing for example: stellar outflows in regions masked by strong reflection nebulae; shocks from high velocity galactic HI clouds; the optical couterparts of supernova remnants; stellar wind-blown bubbles, shells, sheets and filaments and emission nebulosity close to young stellar sources. The spatial extent and detailed morphology of HII regions, OB associations and the wide variety of structures (shells, rings, holes, bubbles, filaments and arcs) over a range of scales from a few arcseconds to tens of degrees can be particularly well studied by H imaging.

The new survey, timely in respect of telescope loading, should commence towards the end of 1996 and will initially include about 160 standard UKST fields. This will then be extended to the outer regions of the Galactic plane and to declinations from +0 to +15 degrees. Exposures will be of the order of 3hours and the survey will take about 3 years to complete. The narrow-band nature of the H filter means that the survey can proceed in grey/bright time when the sky is too bright for normal observations. The photometric integrity of the survey will be assessed via independent narrow band photometry with CCD's on other telescopes and with reference to previously studied objects over a range of UKST fields.

© Copyright Astronomical Society of Australia 1997