Tracing Interstellar Magnetic Field Using Velocity Gradient Technique: Application to Atomic Hydrogen Data
Tracing Interstellar Magnetic Field Using Velocity Gradient Technique: Application to Atomic Hydrogen Data
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DOI：
10.3847/2041-8213/aa6255
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发表时间：
2017-01
期刊：
影响因子：
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通讯作者：
K. Yuen;A. Lazarian
中科院分区：
文献类型：
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作者：
K. Yuen;A. Lazarian
我们对MHD湍流的理解的进步为开发探测磁场的新技术开辟了道路。在MHD湍流中，速度梯度被认为是垂直于磁场的，González-Casanova和Lazarian利用这一事实介绍了一种利用速度质心梯度(VCGS)追踪磁场的新技术。后者可以从光谱观测中获得。我们将该技术应用于GALFA-HI测量数据，然后将我们的技术得到的磁场方向与普朗克极化得到的磁场方向进行了比较。我们发现这两种磁场示踪方法之间有很好的对应关系，通过直观的比较和通过测量极化数据和我们的技术获得的磁场起伏的统计数据，这一点是明显的。这表明VCGS具有测量前景磁场波动的潜力，从而提供了一种分离前景和CMB极化信号的新方法。
The advancement of our understanding of MHD turbulence opens ways to develop new techniques to probe magnetic fields. In MHD turbulence, the velocity gradients are expected to be perpendicular to magnetic fields and this fact was used by González-Casanova & Lazarian to introduce a new technique to trace magnetic fields using velocity centroid gradients (VCGs). The latter can be obtained from spectroscopic observations. We apply the technique to GALFA-H i survey data and then compare the directions of magnetic fields obtained with our technique to the direction of magnetic fields obtained using PLANCK polarization. We find an excellent correspondence between the two ways of magnetic field tracing, which is obvious via the visual comparison and through the measuring of the statistics of magnetic field fluctuations obtained with the polarization data and our technique. This suggests that the VCGs have a potential for measuring of the foreground magnetic field fluctuations, and thus provide a new way of separating foreground and CMB polarization signals.