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The Effect of Star Formation on Molecular Clouds in Dwarf Irregular Galaxies: IC 10 and NGC 6822

G. R. Petitpas·C. D. Wilson
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Abstract

We have observed the 13CO J=2-1, 12CO J=2-1 and 12CO J=3-2 lines at a few locations in the dwarf irregular galaxies IC 10 and NGC 6822 using the James Clerk Maxwell Telescope. In addition, we report the first detection of the 13CO J=3-2 transition in a Local Group galaxy. These low metallicity environments appear to be porous to UV radiation and allow for more efficient heating of molecular gas by nearby HII regions. The high 12CO J=3-2/J=2-1 ratio in NGC 6822 suggests that the 12CO emission is optically thin in this region. This high line ratio is likely the result of its location inside a large HII region with low metallicity and low gas content. In IC 10 we observe structures on a variety of size scales that all appear to be gravitationally bound. This effect may help explain the rather high star formation rate in IC 10.

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G. R. Petitpas, C. D. Wilson. 1997-10-21. The Effect of Star Formation on Molecular Clouds in Dwarf Irregular Galaxies: IC 10 and NGC 6822. https://doi.org/10.1086/305351

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