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Molecular Clouds and the Interstellar Medium in M33

Published online by Cambridge University Press:  03 August 2017

Christine D. Wilson*
Affiliation:
Dept. of Astronomy, 105-24 California Institute of Technology Pasadena, CA U. S. A. 91125

Abstract

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A total of 38 molecular clouds have been mapped in the inner kiloparsec of the nearby galaxy M33. The properties of these clouds (diameters, velocity widths, brightness temperatures, and masses) are very similar to the properties of Galactic giant molecular clouds. The cloud mass spectrum is also similar in the two galaxies, except that the M33 mass spectrum is deficient in the highest mass clouds. A comparison of the interferometer and single dish fluxes shows that only 40% of the CO flux is contained in clouds more massive than 105 M, while 60% of the flux is due to diffuse gas or a fairly smooth distribution of small clouds that cannot be detected with the interferometer. Comparing the CO maps with a high-resolution HI map and optical Hα photometry reveals that peaks in these three components are always found close together. The atomic gas peaks near the molecular clouds are probably produced via photo-dissociation of the molecular gas.

Type
I- Local Group Galaxies
Copyright
Copyright © Kluwer 1991 

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