期刊
ASTROPHYSICAL JOURNAL
卷 604, 期 1, 页码 L49-L52出版社
UNIV CHICAGO PRESS
DOI: 10.1086/383308
关键词
ISM : clouds; ISM : kinematics and dynamics; ISM : magnetic fields; MHD; radiative transfer; turbulence
The magnetic field strength in molecular clouds is a fundamental quantity for theories of star formation. It is estimated by Zeeman splitting measurements in a few dense molecular cores, but its volume-averaged value within large molecular clouds ( over several parsecs) is still uncertain. In this work, we provide a new method to constrain the average magnetic field strength in molecular clouds. We compare the power spectrum of gas density of molecular clouds with that of two 3503 numerical simulations of supersonic MHD turbulence. The numerical simulation with approximate equipartition of kinetic and magnetic energies (model A) yields the column density power spectrum P(k) proportional to k(-2.25+/-0.01), the super-Alfvenic simulation (model B) P(k) proportional to k(-2.71 +/- 0.01). The column density power spectrum of the Perseus, Taurus, and Rosetta molecular cloud complexes is found to be well approximated by a power law P-0(k) proportional to k(-a), with a = 2.74 +/- 0.07, 2.74 +/- 0.08, and 2.76 +/- 0.08, respectively. We conclude that the observations are consistent with the presence of super-Alfvenic turbulence in molecular clouds ( model B), while model A is inconsistent ( more than 99% confidence) with the observations.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据