Turbulence in the ISM

Abstract

The formation of interstellar clouds by turbulence compression is discussed. The 2D fractal dimension of cloud boundaries may be related to the distribution function of projected clump masses within the clouds, n(M) ∝ M-1.7. The three-dimensional mass distribution of clumps, and the stellar mass function as well, may be related to the 3D fractal dimension of clouds, which gives n(M) ∝ M-2.2. Cloud formation often begins on a large scale with a linear instability whose remnant is a well-defined Jeans length for the separation between giant cloud complexes along spiral arms. Subsequent growth of the instability produces turbulence and fractal structure because of motions fed by self-gravity. © Universidad Nacional Autónoma de México.