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Probing magnetic fields in self-gravitating molecular clouds are generally difficult even with the use of the polarimetry. Based on the properties of magneto-hydrodynamic (MHD) turbulence and turbulent reconnection, Velocity Gradient…

Astrophysics of Galaxies · Physics 2019-03-01 Cheng-Han Hsieh , Yue Hu , Shih-Ping Lai , Ka Ho Yuen , Sheng-Yuan Liu , I-Ta Hsieh , Ka Wai Ho , Alex Lazarian

This study proceeds with the development of the technique employing velocity gradients that were identified in (\cite{GL17}, henceforth GL17) as a means of probing magnetic field in interstellar media. We demonstrate a number of practical…

Astrophysics of Galaxies · Physics 2017-05-25 Ka Ho Yuen , A. Lazarian

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…

Astrophysics of Galaxies · Physics 2017-03-15 Ka Ho Yuen , A. Lazarian

Magnetic fields play an important role in the evolution of molecular clouds and star formation. Using the Velocity Gradient Technique (VGT) model, we measured the magnetic field in Orion A using the 12CO, 13CO, and C18O (1-0) emission lines…

Magnetic fields (B-fields) are ubiquitous in the interstellar medium (ISM), and they play an essential role in the formation of molecular clouds and subsequent star formation. However, B-fields in interstellar environments remain…

Astrophysics of Galaxies · Physics 2024-10-18 Archana Soam , Ka Ho Yuen , Ian Stephens , Chi Yan Law , Ka Wai Ho , Simon Coudé

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…

Astrophysics of Galaxies · Physics 2022-04-27 Yue Hu , A. Lazarian , Q. Daniel Wang

Recent development of the velocity gradient technique shows the {\toreferee capability} of the technique in the way of tracing magnetic fields morphology in diffuse interstellar gas and molecular clouds. In this paper, we perform the…

Astrophysics of Galaxies · Physics 2023-02-01 Ka Wai Ho , Alex Lazarian

Recent developments of the Velocity Gradient Technique (VGT) show that the velocity gradients provide a reliable tracing of magnetic field direction in turbulent plasmas. In this paper, we explore the ability of velocity gradients to…

Astrophysics of Galaxies · Physics 2018-09-26 A. Lazarian , Ka Ho Yuen , Ka Wai Ho , Junda Chen , Victor Lazarian , Zekun Lu , Bo Yang , Yue Hu

The detection of primordial B-mode polarization is still challenging due to the relatively low amplitude compared to the galactic foregrounds. To remove the contribution from the foreground, a comprehensive picture of the galactic magnetic…

Astrophysics of Galaxies · Physics 2020-07-07 Yue Hu , A. Lazarian

As a novel approach for tracing interstellar magnetic fields, the Velocity Gradient Technique (VGT) has been proven to be effective for probing magnetic fields in the diffuse interstellar medium (ISM). In this work, we verify the VGT in a…

Astrophysics of Galaxies · Physics 2022-01-26 Mingrui Liu , Yue Hu , Alex Lazarian

The recent development of the Velocity Gradient Technique allows observers to map magnetic field orientations and magnetization using the direction of velocity gradients. Aside from the directions, amplitudes of velocity gradients also…

Astrophysics of Galaxies · Physics 2020-05-15 Ka Ho Yuen , A. Lazarian

Magnetic fields are ubiquitous in the interstellar medium but are notoriously difficult to study through observation. Making use of the advances in our understanding of MHD turbulence and turbulent reconnection, the Velocity Gradient…

Astrophysics of Galaxies · Physics 2020-01-08 Yue Hu , Ka Ho Yuen , Alex Lazarian

Magnetic fields are a defining yet enigmatic aspect of the interstellar medium (ISM), with their three-dimensional mapping posing a substantial challenge. In this study, we harness the innovative Velocity Gradient Technique (VGT),…

Astrophysics of Galaxies · Physics 2024-01-15 Tyler Schmaltz , Yue Hu , A. Lazarian

Probing magnetic fields in Giant Molecular Clouds is often challenging. Fortunately, recently simulations show that analysis of velocity gradients (the Velocity Gradient Technique) can be used to map out the magnetic field morphology of…

Astrophysics of Galaxies · Physics 2019-11-06 Yue Hu , Ka Ho Yuen , A. Lazarian , Laura M. Fissel , P. A. Jones , M. R. Cunningham

We identify velocity channel map intensities as a new way to trace magnetic fields in turbulent media. This work makes use of both of the modern theory of MHD turbulence predicting that the magnetic eddies are aligned with the local…

Astrophysics of Galaxies · Physics 2018-02-07 A. Lazarian , Ka Ho Yuen

Magnetic fields, while ubiquitous in many astrophysical environments, are challenging to measure observationally. Based on the properties of anisotropy of eddies in magnetized turbulence, the Velocity Gradient Technique is a method…

The Velocity Gradients Technique (VGT) and the Probability Density Functions (PDFs) of mass density are tools to study turbulence, magnetic fields, and self-gravity in molecular clouds. However, self-absorption can significantly make the…

Astrophysics of Galaxies · Physics 2021-01-20 Yue Hu , A. Lazarian

Strong Alfv\'enic turbulence develops eddy-like motions perpendicular to the local direction of magnetic fields. This local alignment induces velocity gradients perpendicular to the local direction of the magnetic field. We use this fact to…

Astrophysics of Galaxies · Physics 2017-01-25 Diego F. González-Casanova , A. Lazarian

Understanding how star formation is regulated requires studying the energy balance between turbulence, magnetic fields, stellar feedback, and gravity within molecular clouds. However, identifying the transition region where the gravity…

Astrophysics of Galaxies · Physics 2020-07-22 Yue Hu , Alex Lazarian , Ka Ho Yuen

Probing magnetic fields in astrophysical environments is both important and challenging. The Gradient Technique (GT) is a new tool for tracing magnetic fields, rooted in the properties of magnetohydrodynamic (MHD) turbulence and turbulent…

Astrophysics of Galaxies · Physics 2024-06-18 Yue Hu , Alex Lazarian
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