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Paper: Small-Scale Molecular Structure in the Galaxy
Volume: 365, SINS — Small Ionized and Neutral Structures in the Diffuse Interstellar Medium
Page: 177
Authors: Heithausen, A.
Abstract: I will summarize the current knowledge on molecular gas in the diffuse interstellar medium (ISM). H2 absorption line observations show that molecular gas is ubiquitous in the diffuse ISM of our Galaxy. The analysis of such data suggests that the molecular gas is concentrated in small dense clumps. Direct observation of the structure is possible with the serendipitous detection of small-area molecular structures in several CO lines in regions with very low shielding of the interstellar radiation field. Based on a combination of low and high-angular resolution observations it is found that the clouds are composed of clumps with sizes of a few hundred AU and volume densities exceeding 1000 cm−3; they have a fractal structure. I will show that such structures might be an abundant phenomenon in the diffuse interstellar medium, however so far not recognized as such due to their small sizes.
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