On the structure of self-gravitating molecular clouds

被引:41
作者
Ossenkopf, V
Klessen, RS
Heitsch, F
机构
[1] Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany
[2] Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA
[3] Max Planck Inst Astron, D-69117 Heidelberg, Germany
关键词
hydrodynamics; ISM : clouds; ISM : magnetic fields; ISM : kinematics and dynamics; ISM : structure; turbulence;
D O I
10.1051/0004-6361:20011324
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
To study the interaction of star-formation and turbulent molecular cloud structuring, we analyse numerical models and observations of self-gravitating clouds using the Delta -variance as statistical measure for structural characteristics. In the models we resolve the transition from purely hydrodynamic turbulence to gravitational collapse associated with the formation and mass growth of protostellar cores. We compare models of driven and freely decaying turbulence with and without magnetic fields. Self-gravitating supersonic turbulence always produces a density structure that contains most power on the smallest scales provided by collapsed cores as soon as local collapse sets in. This is in contrast to non-self-gravitating hydrodynamic turbulence where the Delta -variance is dominated by large scale structures. To detect this effect in star-forming regions observations have to resolve the high density contrast of protostellar cores with respect to their ambient molecular cloud. Using the 3 mm continuum map of a star-forming cluster in Serpens we show that the dust emission traces the full density evolution. On the contrary, the density range accessible by molecular line observations is insufficient for this analysis. Only dust emission and dust extinction observations are able to to determine the structural parameters of star-forming clouds following the density evolution during the gravitational collapse.
引用
收藏
页码:1005 / 1016
页数:12
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