arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2201.07970astro-ph.GA
收藏

中心分子带上三维磁场的分解

Decomposing Magnetic Fields in Three Dimensions over the Central Molecular Zone

Yue Hu, A. Lazarian, Q. Daniel Wang

摘要:

用传统的方法测量星际介质中的磁场并获得其沿视线方向的分布是一个很大的挑战。速度梯度技术(VGT),它利用磁流体(MHD)湍流的各向异性,提供了一个有吸引力的解决方案。针对中心分子区(CMZ),我们通过将VGT应用于$\rm ^{12}CO$和$\rm ^{13}CO$(J = 1-0)数据立方体来测试这种方法。我们首先使用SCOUSEPY算法将CO谱线辐射分解为独立的速度分量,然后通过VGT构造伪Stokes参数来映射三维的天平面磁场。我们提出了分解的磁场地图,并探讨其意义。虽然视线的综合磁场的方向被证明是一致的,从普朗克调查在353 GHz的极化尘埃排放,个别速度分量可能会表现出不同的磁场。根据分解后的磁场,提出了一种CMZ中磁场位形的计算方法。特别是,我们观察到一个几乎垂直的磁场方向在密集的团块附近的Sgr B2和周围的Sgr A* 的流出区域的变化。两个高速结构与膨胀环在CMZ显示出不同的旋转磁场结构。这些结果表明VGT分解速度或密度相关的磁结构的潜在力量。

英文摘要:

Measuring magnetic fields in the interstellar medium and obtaining their distribution along line-of-sight is very challenging with the traditional techniques. The Velocity Gradient Technique (VGT), which utilizes anisotropy of magnetohydrodynamic (MHD) turbulence, provides an attractive solution. Targeting the central molecular zone (CMZ), we test this approach by applying the VGT to $\rm ^{12}CO$ and $\rm ^{13}CO$ (J = 1-0) data cubes. We first used the SCOUSEPY algorithm to decompose the CO line emissions into separate velocity components, and then we constructed pseudo-Stokes parameters via the VGT to map the plane-of-the-sky magnetic fields in three-dimension. We present the decomposed magnetic field maps and investigate their significance. While the line-of-sight integrated magnetic field orientation is shown to be consistent with the polarized dust emission from the Planck survey at 353 GHz, individual velocity components may exhibit different magnetic fields. We present a scheme of magnetic field configuration in the CMZ based on the decomposed magnetic fields. In particular, we observe a nearly vertical magnetic field orientation in the dense clump near the Sgr B2 and a change in the outflow regions around the Sgr A*. Two high-velocity structures associated with an expanding ring in the CMZ show distinct swirling magnetic field structures. These results demonstrate the potential power of the VGT to decompose velocity or density-dependent magnetic structures.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑