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Related papers: Alignment of Dust by Radiative Torque: Recent Deve…

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Grain alignment theory suggests that grains should be aligned in circumstellar regions and the observational data available supports this conclusion. We discuss the alignment of grains via (1) magnetic relaxation, (2) mechanical processes,…

Astrophysics · Physics 2007-05-23 Lazarian A

We apply the theory of radiative torque (RAT) alignment for studying protoplanetary disks around a T-Tauri star and perform 3D radiative transfer calculations to provide the expected maps of polarized radiation to be compared with…

Earth and Planetary Astrophysics · Physics 2017-04-19 Ryo Tazaki , Alexandre Lazarian , Hideko Nomura

We study the alignment of irregular dust grains by mechanical torques due to the drift of grains through the ambient gas. We first calculate mechanical torques (MATs) resulting from specular reflection of gas atoms for seven irregular…

Astrophysics of Galaxies · Physics 2018-01-31 Thiem Hoang , Jungyeon Cho , A. Lazarian

We study the physical processes that affect the alignment of grains subject to radiative torques (RATs). To describe the action of RATs, we use the analytical model (AMO) of RATs introduced in Paper I. We focus our discussion on the…

Astrophysics · Physics 2009-06-23 Thiem Hoang , Alex Lazarian

Magnetic fields ($\textbf{B}$) are an important factor that controls the star formation process. The leading method to observe $\textbf{B}$ is using polarized thermal emission from dust grains aligned with $\textbf{B}$. However, in dense…

Astrophysics of Galaxies · Physics 2023-06-16 Nguyen Chau Giang , Thiem Hoang , Jeong-Gyu Kim , Le Ngoc Tram

Magnetic fields are thought to influence the formation and evolution of circumstellar envelopes around evolved stars. Thermal dust polarization from aligned grains is a promising tool for probing magnetic fields and dust properties in these…

Solar and Stellar Astrophysics · Physics 2024-12-05 Bao Truong , Thiem Hoang , Nguyen Chau Giang , Pham Ngoc Diep , Dieu D. Nguyen , Nguyen Bich Ngoc

The radiative torque (RAT) alignment of interstellar grains with ordinary paramagnetic susceptibilities has been supported by earlier studies. The alignment of such grains depends on the so-called RAT parameter $q^{\max}$ that is determined…

Astrophysics of Galaxies · Physics 2016-11-15 Thiem Hoang , A. Lazarian

Aligned grains present a foreground for cosmic microwave emission studies. We review basic physical processes involved in grain alignment and discuss the niches for different alignment mechanisms. We show that mechanisms which were favored…

Astrophysics · Physics 2007-05-23 A. Lazarian , Jungyeon Cho

Polarized emission from interstellar dust grains is commonly used to infer information about the underlying magnetic field from the diffuse interstellar medium to molecular cloud cores. Therefore, the ability to accurately determine…

Solar and Stellar Astrophysics · Physics 2026-02-19 Marco Leon Scheiter , Sebastian Wolf

Polarimetry is one of the most informative techniques of studying magnetic fields in molecular clouds. How reliable the interpretation of the polarization maps in terms of magnetic fields is the issue that the grain alignment theory…

Astrophysics · Physics 2016-08-30 A. Lazarian , J. Cho

Polarized microwave emission from dust is an important foreground that may contaminate polarized CMB studies unless carefully accounted for. Modeling of polarization from dust requires a quantitative understanding of grain alignment. I…

Astrophysics · Physics 2008-11-07 A. Lazarian

We study the physical processes inducing the alignment of the grain axis of maximum inertia moment with the angular momentum (${\bf J}$, i.e., internal alignment) and of ${\bf J}$ with the magnetic field (i.e., external alignment) of very…

Astrophysics of Galaxies · Physics 2022-11-30 Thiem Hoang , Le Ngoc Tram , Vo Hong Minh Phan , Nguyen Chau Giang , Nguyen Thi Phuong , Nguyen Duc Dieu

Interstellar dust grain alignment causes polarization from UV to mm wavelengths, allowing the study of the geometry and strength of the magnetic field. Over last couple of decades observations and theory have led to the establishment of the…

We generalize the magnetically enhanced radiative torque (MRAT) alignment theory for general astrophysical environments described by a dimensionless parameter $U/(n_{1}T_{2})$ with $U$ local radiation strength, $n_{1}=n_{\rm H}/(10{\rm…

Astrophysics of Galaxies · Physics 2025-09-23 Thiem Hoang

We consider grains with superparamagnetic inclusions and report two new condensed matter effects that can enhance the internal relaxation of the energy of a wobbling grain, namely, superparamagnetic Barnett relaxation, as well as, an…

Astrophysics · Physics 2009-11-13 A. Lazarian , T. Hoang

Context: Aligned dust grains are commonly exploited to probe the magnetic field orientation. However, the exact physical processes that result in a coherent large-scale grain alignment are far from being constrained. Aims: In this work, we…

Astrophysics of Galaxies · Physics 2023-07-05 Stefan Reissl , Paul Meehan , Ralf S. Klessen

Dust polarization induced by aligned grains is widely used to study magnetic fields in various environments, including star-forming regions. However, the question of to what optical depth grain alignment still exists in a dense molecular…

Astrophysics of Galaxies · Physics 2021-03-03 Thiem Hoang , Le Ngoc Tram , Hyeseung Lee , Pham Ngoc Diep , Nguyen Bich Ngoc

How and when in the star formation sequence do dust grains start to grow into pebbles is a cornerstone question to both star and planet formation. We compute the polarized radiative transfer from a model solar-type protostellar core, using…

The polarization of starlight and thermal dust emission from aligned non-spherical grains provides a powerful tool for tracing magnetic field morphologies and strengths in diffuse interstellar medium to star-forming regions, and…

Astrophysics of Galaxies · Physics 2025-07-11 Saikhom Pravash , Thiem Hoang , Archana Soam , Eun Jung Chung , Pham Ngoc Diep , Nguyen Bich Ngoc , Le Ngoc Tram

Polarization of starlight and thermal dust emission caused by aligned dust grains is a valuable tool to characterize magnetic fields (B-fields) and constrain dust properties. However, the physics of grain alignment is not fully understood.…

Astrophysics of Galaxies · Physics 2024-09-10 Nguyen Bich Ngoc , Thiem Hoang , Pham Ngoc Diep , Le Ngoc Tram