Magnetic Fields in Molecular Cloud Cores
| dc.creator | Basu, Shantanu | |
| dc.date | 2004-10-22 | |
| dc.date.accessioned | 2026-07-07T02:15:26Z | |
| dc.date.available | 2026-07-07T02:15:26Z | |
| dc.description | Observations of magnetic field strengths imply that molecular cloud fragments are individually close to being in a magnetically critical state, even though both magnetic field and column density measurements range over two orders of magnitude. The turbulent pressure also approximately balances the self-gravitational pressure. These results together mean that the one-dimensional velocity dispersion $\sigv$ is proportional to the mean \Alf speed of a cloud $\va$. Global models of MHD turbulence in a molecular cloud show that this correlation is naturally satisfied for a range of different driving strengths of the turbulence. For example, an increase of turbulent driving causes a cloud expansion which also increases $\va$. Clouds are in a time averaged balance but exhibit large oscillatory motions, particularly in their outer rarefied regions. We also discuss models of gravitational fragmentation in a sheet-like region in which turbulence has already dissipated, including the effects of magnetic fields and ion-neutral friction. Clouds with near-critical mass-to-flux ratios lead to subsonic infall within cores, consistent with some recent observations of motions in starless cores. Conversely, significantly supercritical clouds are expected to produce extended supersonic infall. | |
| dc.description | 10 pages, 6 figures, in Young Local Universe, Proceedings of XXXIXth Rencontres de Moriond, eds. A. Chalabaev, T. Fukui, T. Montmerle, and J. Tran-Thanh-Van, (Editions Frontieres, Paris) | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0410534 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0410534 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/8408 | |
| dc.subject | Astrophysics | |
| dc.title | Magnetic Fields in Molecular Cloud Cores | |
| dc.type | text |