Gravitational Infall onto Molecular Filaments. II. Externally Pressurized Cylinders
Abstract
Two aspects of the evolution of externally pressurized, hydrostatic filaments are discussed. (1) The free-fall accretion of gas onto such a filament will lead to filament parameters (specifically, FWHM-column-density relations) inconsistent with the observations of Arzoumanian et al., except for two cases: for low-mass, isothermal filaments, agreement is found as in the analysis by Fischera & Martin. Magnetized cases, for which the field scales weakly with the density as Bvpropn 1/2, also reproduce observed parameters. (2) Realistically, the filaments will be embedded not only in gas of non-zero pressure, but also of non-zero density. Thus, the appearance of sheet-embedded filaments is explored. Generating a grid of filament models and comparing the resulting column density ratios and profile shapes with observations suggests that the three-dimensional filament profiles are intrinsically flatter than isothermal, beyond projection and evolution effects.
- Publication:
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The Astrophysical Journal
- Pub Date:
- October 2013
- DOI:
- 10.1088/0004-637X/776/1/62
- arXiv:
- arXiv:1308.5637
- Bibcode:
- 2013ApJ...776...62H
- Keywords:
-
- gravitation;
- ISM: clouds;
- methods: analytical;
- stars: formation;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 15 pages, 7 figures, accepted by ApJ