http://arxiv.org/abs/1908.09488
Magnetic fields are ubiquitous in the interstellar medium but are notoriously difficult to study with observations. Making use of the advances in the understanding of MHD turbulence and turbulent reconnection, a new technique, namely, Velocity Gradient Technique (VGT) was suggested and successfully applied to study magnetic field with spectroscopic data. Applying the tools developed for the VGT to the intensity distribution, we introduce the Intensity Gradients Technique (IGT) as a complementary tool that can be used synergetically with the VGT. We apply IGT to a diffuse HI region selected from GALFA-HI survey and compare the intensity gradient maps with those obtained with velocity gradients as well as Planck polarization measurements. We demonstrate the possibility of using IGT and VGT for studying both the magnetic field and identifying shocks in the diffuse interstellar medium. We also explore the ability of the IGT, alone and together with the VGT and polarimetry to be used in search of self-gravitating regions, as well as for measuring Alfvenic Mach number and Sonic Mach number. We compare the IGT with the Histogram of Relative Orientation (HRO), which also utilizes intensity gradients but in a different way.
Y. Hu, K. Yuen and A. Lazarian
Tue, 27 Aug 19
23/85
Comments: 14 pages, 11 figures, submitted to ApJ
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