Radio Continuum Mapping of the Spiral Galaxy NGC 6946
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Session 19 -- Gas and Star Formation in Spiral Galaxies
Display presentation, Wednesday, January 12, 9:30-6:45, Salons I/II Room (Crystal Gateway)

## [19.03] Radio Continuum Mapping of the Spiral Galaxy NGC 6946

Scott D.~Hyman (Sweet Briar College), Schuyler D.~Van Dyk (NRC/NRL), Kurt W.~Weiler (Naval Research Lab), Richard A.~Sramek (NRAO/VLA), Rachel E.~Virden (Sweet Briar College)

We have combined radio continuum observations of the giant spiral galaxy NGC~6946 at 20 and 6 cm made with the VLA in various array configurations, which were originally used to monitor the radio supernova SN~1980K (Weiler et al.~1986, 1992). The maps we derive from this dataset are of superior signal-to-noise ($\sigma \simlt 0.04$ mJy/beam at 20 cm) and spatial resolution ($\sim 4$'' at 20 cm) to those previously published by other investigators. We present a preliminary atlas of individual thermal and nonthermal sources, including flux densities and spectral indices, and make a comparison with optical H$\alpha$ maps (e.~g., Bonnarel et al.~1986). In particular, we identify the radio counterpart to the very luminous X-ray supernova remnant (Schlegel 1993), which is $\sim 2000$ times more powerful than Cas~A in the radio. We also give an upper limit for the large scale nonthermal cosmic ray background of the galaxy.