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T.T. Helfer (UC Berkeley), M. Murgia (CNR Bologna/INAF), R. Ekers (ATNF/CSIRO), L. Blitz (UC Berkeley), L. Moscadelli (INAF), T. Wong (ATNF/CSIRO/UNSW), R. Paladino (INAF/U Cagliari)
We present a comparison of the global RC, FIR, and CO in 24 galaxies selected from the BIMA Survey of Nearby Galaxies and a detailed study of the high-resolution (6'') CO-RC correlation in a subset of 9 sources. On global scales, the correlations between the CO-RC, FIR-RC, and FIR-RC are comparably tight. At 6'' resolution, the CO and RC emission is as tightly correlated as its global value, down to 100 pc size scales. The CO-RC correlation is linear with a dispersion that is less than a factor of 2. Despite the low dispersion in the correlation, there are systematic variations in the CO-RC ratio which are about twice as large as the dispersion and which tend to be organized along spiral arms on size scales much larger than the resolution of the observations. Unlike the FIR-RC correlation, there is no systematic trend in CO-RC as a function of radius in galaxies. We speculate that the radial decrease of FIR-RC seen on arcminute scales is a consequence of the relatively larger annular area taken up by spiral arms at small radius than at large radius, and that high-resolution Spitzer images will show detailed spatial correlation between the FIR and RC and CO. We suggest that the excellent correlation between the RC, CO and FIR emission is a consequence of regulation by hydrostatic pressure in galaxies.
This research was funded in part by NSF grant 0228963 to the Radio Astronomy Laboratory at UC Berkeley.
The author(s) of this abstract have provided an email address for comments about the abstract: thelfer@astro.berkeley.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.