Radio Continuum Mapping of the Spiral Galaxy NGC 4321

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Session 107 -- Galaxies: Morphology and Interactions
Display presentation, Thursday, 12, 1995, 9:20am - 6:30pm

[107.11] Radio Continuum Mapping of the Spiral Galaxy NGC 4321

Scott D.~Hyman (Sweet Briar College), Kurt W.~Weiler (Naval Research Lab), Schuyler D.~Van Dyk (UC Berkeley), Richard A.~Sramek (NRAO/VLA), Wenhui Liang (Sweet Briar College)

\noindent We have combined numerous, short radio continuum observations of the Virgo Cluster spiral galaxy NGC~4321 (M~100) made at 20 and 6 cm with the Very Large Array (VLA) to produce a deep map of the galaxy. These observations were originally taken for monitoring the radio supernova SN~1979C (Weiler et al.~1986, ApJ, 310, 790; 1991, ApJ, 380, 161) and is analogous to our recent work on NGC~6946 (Hyman et al.~1993, BAAS 25, 1322) using observations taken for monitoring SN~1980K. The maps we derive for NGC 4321 are of superior sensitivity ($\sigma \simlt 0.05$ mJy/beam at 20 cm) and spatial resolution ($\sim 2"$ at 20 cm) to those previously published by other investigators (e.~g., Knapen et al.~1993, ApJ, 416, 563). We present preliminary measurements and analyses of detected thermal and nonthermal sources, including flux densities, spectral indices, and luminosities, particularly for the very strong circumnuclear radio source, known as a site of intense star formation (e.~g., Arsenault et al.~1988, A{\&}A, 200, 29). We also make comparisons of our radio maps with existing data at other wavelengths.

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