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Related papers: Two modes of carbonaceous dust alignment

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Alignment of dust grains in astrophysical environments results in the polarization of starlight as well as the polarization of radiation emitted by dust. We demonstrate the advances in grain alignment theory allow the use of linear and…

Astrophysics of Galaxies · Physics 2019-10-02 A Lazarian , Thiem Hoang

Grain alignment by radiative torques (RATs) has been extensively studied for various environment conditions, including interstellar medium, dense molecular clouds, and accretion disks, thanks to significant progress in observational,…

Astrophysics of Galaxies · Physics 2015-06-22 Thiem Hoang , A. Lazarian

Polarization arising from aligned dust grains presents a unique opportunity to study magnetic fields in the diffuse interstellar medium and molecular clouds. Polarization from circumstellar regions, accretion disks and comet atmospheres can…

Astrophysics of Galaxies · Physics 2016-06-21 A. Lazarian , B-G Andersson , Thiem Hoang

Alignment of dust by radiative torques (RATs) has proven to be the most promising mechanism to explain alignment in various astrophysical environments, from comet atmospheres to accretion disks, molecular clouds, and diffuse interstellar…

Astrophysics of Galaxies · Physics 2009-01-21 A. Lazarian , Thiem Hoang

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

We study the efficiency of grain alignment by radiative torques (RATs) for an ensemble of irregular grains. The grains are modeled as ensembles of oblate and prolate spheroids, deformed as Gaussian random ellipsoids, and their scattering…

Astrophysics of Galaxies · Physics 2021-06-02 Joonas Herranen , A. Lazarian , Thiem Hoang

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

Radiative torques on irregular dust grains, in addition to producing superthermal rotation, play a direct dynamical role in the alignment of interstellar dust with the local magnetic field. The equations governing the orientation of…

Astrophysics · Physics 2009-10-28 B. T. Draine , Joseph C. Weingartner

The linear polarization of thermal dust emission provides a powerful tool to probe interstellar and circumstellar magnetic fields, because aspherical grains tend to align themselves with magnetic field lines. While the Radiative Alignment…

We reveal a deep connection between alignment of dust grains by RAdiative torques (RATs) and MEchanical Torques (METs) and rotational disruption of grains introduced by Hoang et al. (2019). The disruption of grains happens if they have…

Astrophysics of Galaxies · Physics 2021-02-17 A. Lazarian , Thiem Hoang

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

We study the internal and external alignment of carbonaceous grains, including graphite and hydrogenated amorphous carbon (HAC), in the interstellar medium (ISM) within the RAdiative Torque (RAT) paradigm. For internal alignment (IA), we…

Astrophysics of Galaxies · Physics 2023-01-20 Thiem Hoang , Vo Hong Minh Phan , Le Ngoc Tram

While the problem of grain alignment was posed more than 60 years ago the quantitative model of grain alignment that can account for the observed polarization arising from aligned grains has been formulated only recently. The quantitative…

Astrophysics of Galaxies · Physics 2009-03-09 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

Several mechanisms have been proposed to explain the alignment of grains with the interstellar magnetic field, including paramagnetic dissipation, radiative torques, and supersonic gas-grain streaming. These must compete with disaligning…

Astrophysics · Physics 2008-11-26 Joseph C. Weingartner

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

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

Earlier studies of grain alignment dealt mostly with interstellar grains that have strong internal relaxation of energy which aligns grain axis of maximum moment of inertia with respect to grain's angular momentum. In this paper, we study…

Astrophysics · Physics 2010-01-15 Thiem Hoang , Alex Lazarian

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 and rotational disruption of dust grains at the centre of our Galaxy using polarized thermal dust emission observed by SOFIA/HAWC+ and JCMT/SCUPOL at 53, 216, and 850 $\mu$m. We analyzed the relationship between the…

Astrophysics of Galaxies · Physics 2023-05-01 M. S. Akshaya , Thiem Hoang
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