Polarized CO Emission from Molecular Clouds
Polarized CO Emission from Molecular Clouds
复制标题
分子云的偏振 CO 发射
DOI：
--
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Edinburgh
中科院分区：
文献类型：
--
作者：
J. Greaves;W. Holland;P. Friberg;W.R.F. Dent Joint Astronomy Centre;R. Observatory;Edinburgh
在星际介质中首次探测到了线偏振、非磁化、旋转线。这种效应发生在有磁场的分子云中，并跟踪磁场方向，为尘埃发射偏振测量提供了一种替代技术。线偏振机理与脉泽相似，但偏振度较低(~1%)。我们在分子云S140和DR21(暂定)中探测到了对银河中心及其周围的“2PC环”的影响，其谱线为COJ=2-1和J=3-2，13COJ=2-1。推导的磁场方向与前人的尘埃偏振测量结果吻合较好，证实了线极化是一种真实的效应。这项新技术将在尘埃偏振太弱的源上有用，也可以在已知云层速度结构的情况下用于研究磁场的三维形态。
Linearly polarized, nonmasing, rotational lines have been detected for the first time in the interstellar medium. This effect occurs in molecular clouds with a magnetic field and traces the field direction, offering an alternative technique to dust emission polarimetry. The line polarization mechanism is similar to that in masers, but with lower degrees of polarization (~1%). We have detected the effect toward the Galactic center and its surrounding "2 pc ring" and in the molecular clouds S140 and DR 21 (tentatively), in the lines CO J=2-1 and J=3-2 and 13CO J=2-1. The deduced magnetic field directions agree well with previous dust polarimetry results, confirming that the line polarization is a real effect. This new technique will be useful in sources that are too faint for dust polarimetry and can also be used to investigate the three-dimensional morphology of magnetic fields in cases in which the velocity structure of the clouds is known.