An Imaging Survey of the Northern Galactic H Emission with Arcminute Resolution

An Imaging Survey of the Northern Galactic H Emission with Arcminute Resolution

Brian Dennison
John H. Simonetti
Gregory A. Topasna

Martin Observatory, Institute for Particle Physics and Astrophysics, Physics Department, Virginia Tech, Blacksburg VA 24061, USA
dennison@astro.phys.vt.edu, jhs@vt.edu, topasna@astro.phys.vt.edu

Abstract:

We present preliminary results from a high-resolution, high-sensitivity imaging survey of the northern galactic H emission. The survey is carried out using the Spectral Line Imaging Camera (SLIC) which incorporates a fast (f/1.2) lens attached to a cryogenic CCD in combination with a narrowband interference filter. The pixel size is 1.6 arcminutes and the diameter of each field is 10 degrees. The fast optics, narrow bandpass (1.7 nm) filter, and high quantum-efficiency, low-noise CCD yield a high brightness sensitivity to H emission on arcminute scales. This gives an equivalent sensitivity to emission measure structure below 1 pc cm. Some faint features detected include a supershell connected with the star forming region W4 extending 7 degrees above the galactic plane, and filaments possibly related to galactic loops II and III. In addition, we have carried out deep observations of fields in which anisotropies in the cosmic microwave background radiation have been detected. Our observations place stringent limits upon the contribution to the apparent microwave fluctuations from free-free emission in the galactic foreground.

Keywords: Surveys -- ISM: bubbles -- ISM: clouds -- ISM: HII regions -- ISM: structure -- ISM: supernova remnants

б© Copyright Astronomical Society of Australia 1997