English
Related papers

Related papers: Cosmic rays and grain alignment

200 papers

We present extensive calculations on the efficiency of grain alignment by the Davis-Greenstein mechanism. We model the grains as oblate spheroids with arbitrary axis ratios. Our description of the grain dynamics includes (i) magnetic…

Astrophysics · Physics 2010-10-27 W. G. Roberge , A. Lazarian

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…

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

Thermal dust polarization is a powerful tool to probe magnetic fields ($\textbf{B}$) and grain properties. However, a systematic study of the dependence of dust polarization on grain properties in protostellar environments is not yet…

Astrophysics of Galaxies · Physics 2024-03-14 Nguyen Chau Giang , Thiem Hoang

Dust grains drift through the interstellar medium (ISM) and are aligned with the magnetic field. Here we study the effect of grain alignment and grain motion on grain growth in molecular clouds (MCs). We first discuss the characteristic…

Astrophysics of Galaxies · Physics 2022-04-06 Thiem Hoang

The degree to which interstellar grains align with respect to the interstellar magnetic field depends on disaligning as well as aligning mechanisms. For decades, it was assumed that disalignment was due primarily to the random angular…

Astrophysics of Galaxies · Physics 2015-05-13 Margaret E. Jordan , Joseph C. Weingartner

Dust polarization induced by aligned non-spherical grains acts as an important tool to trace the magnetic field (B-field) morphologies and strengths in molecular clouds and constrain grain properties and their alignment mechanisms. The…

Astrophysics of Galaxies · Physics 2026-03-03 Saikhom Pravash , Thiem Hoang , Archana Soam , Qi-Lao Gu , Tie Liu , Pham Ngoc Diep , Le Ngoc Tram , Nguyen Bich Ngoc

Calculations are performed for the linear polarization of starlight due to extinction by aligned dust grains when the starlight traverses a medium with irregular magnetic fields. This medium is intended to represent the optically thick…

Astrophysics · Physics 2009-10-31 D. S. Wiebe , W. D. Watson

In this paper, we present preliminary results illustrating the effect of cosmic rays on solid-phase chemistry in models of both TMC-1 and several sources with physical conditions identical to TMC-1 except for hypothetically enhanced…

Astrophysics of Galaxies · Physics 2018-07-11 Christopher N. Shingledecker , Jessica D. Tennis , Romane Le Gal , Eric Herbst

The alignment of dust grains with the ambient magnetic field produces polarization of starlight as well as thermal dust emission. Using the archival SOFIA/HAWC+ polarimetric data observed toward $\rho$ Ophiuchus (Oph) A cloud hosted by a B…

Astrophysics of Galaxies · Physics 2021-01-25 Le Ngoc Tram , Thiem Hoang , Hyeseung Lee , Fabio Santos , Archana Soam , Pierre Lesaffre , Antoine Gusdorf , William Reach

We aim to investigate the polarization properties of a starless core in a very early evolutionary stage. Linear polarization data reveal the properties of the dust grains in the distinct phases of the interstellar medium. Our goal is to…

Solar and Stellar Astrophysics · Physics 2014-09-17 Felipe Alves , Pau Frau , Josep M. Girart , Gabriel A. P. Franco , Fábio P. Santos , Helmut Wiesemeyer

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…

Observational studies have reported that cosmic filaments on the megaparsec scale exhibit rotational motion. Subsequent simulation studies have shown qualitative agreement with these findings, but quantitative discrepancies remain due to…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-07 Peng Wang , Xiao-Xiao Tang , Hao-Da Wang , Noam I. Libeskind , Elmo Tempel , Wei Wang , Youcai Zhang , Ming-Jie Sheng , Hao-Ran Yu , Haojie Xu

Dust clouds are ubiquitous in the atmospheres of hot Jupiters and affect their observable properties. The alignment of dust grains in the clouds and resulting dust polarization is a promising method to study magnetic fields of exoplanets.…

Earth and Planetary Astrophysics · Physics 2021-08-24 Thiem Hoang , A. Lazarian

We study the combined impact of magnetic mirroring and focusing on the ionization by cosmic rays (CRs) in dense molecular clouds and circumstellar disks. We show that for effective column densities of up to $\sim10^{25}$ cm$^{-2}$ (where…

High Energy Astrophysical Phenomena · Physics 2018-08-29 Kedron Silsbee , Alexei V. Ivlev , Marco Padovani , Paola Caselli

Our aim is to study the polarization of thermal dust emission to see if the alignment of grain by radiative torques could explain the observed relation between the degree of polarization and the intensity in dense cores. Predictions are…

Astrophysics · Physics 2009-11-11 V. -M. Pelkonen , M. Juvela , P. Padoan

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

Polarized (sub)millimeter emission from dust grains in circumstellar disks was initially thought to be due to grains aligned with the magnetic field. However, higher resolution multi-wavelength observations along with improved models found…

The standard model of cosmic ray heating-induced desorption of interstellar ices is based on a continuous representation of the sporadic desorption of ice mantle components from classical (0.1 micron) dust grains. This has been re-evaluated…

Solar and Stellar Astrophysics · Physics 2022-08-17 Jonathan M. C. Rawlings

The short term variability of the Galactic cosmic ray flux (CRF) reaching Earth has been previously associated with variations in the global low altitude cloud cover. This CRF variability arises from changes in the solar wind strength.…

Astrophysics · Physics 2009-11-07 Nir J. Shaviv