Very Large Array 14 GHz Continuum Imaging of Nearby, Star-Forming Galaxies

Type Conference Paper
Names Asra Nizami, J. M. Cannon, A. A. Kepley, L. Chomiuk, J. C. Lee, K. B. McQuinn, E. D. Skillman, E. M. Wilcots, A. Williams
Proceedings Title American Astronomical Society
Conference Name AAS Meeting #223, #355.15
Volume 223
Date January 1, 2014
Library Catalog
Abstract We present new KU band radio continuum imaging of three nearby starburst dwarf galaxies, NGC4449, NGC2366 and Holmberg II, obtained with the Karl G. Jansky Very Large Array. The wide bandwidth (2 GHz) allows a sensitive examination of the nature of radio continuum emission between 13 and 15 GHz. We compare these continuum images with tracers of very recent star formation (H alpha emission, probing the most recent few Myr) and with tracers of intermediate timescale star formation (GALEX near UV emission, probing timescales of ~200 Myr). When summed over the entire 2 GHz bandpass, the radio continuum emission morphology is qualitatively similar to that of the regions of highest H alpha surface brightness; however, in all three galaxies, there are regions of H alpha emission that are not detected at this sensitivity level in the 14 GHz continuum. Imaging individual 128 MHz spectral windows allows us to examine the variation of flux density with frequency on a spatially resolved basis. Combining with lower-frequency radio continuum imaging allows a separation of thermal and non-thermal emission components. A.N. and J.M.C. acknowledge support from Macalester College that made this work possible.
UW-Madison Astronomy Home