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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

We calculate the wavelength dependence of the ratio of the linear polarization degree to extinction (polarizing efficiency) $P(\lambda)/A(\lambda)$ from the ultraviolet to near-infrared. The prolate and oblate particles with aspect ratios…

Astrophysics · Physics 2009-11-13 N. V. Voshchinnikov , H. K. Das

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

We compute polarization maps for molecular cloud cores modeled as magnetized singular isothermal toroids, under the assumption that the emitting dust grains are aspherical and aligned with the large-scale magnetic field. We show that,…

Astrophysics · Physics 2009-11-10 J. Goncalves , D. Galli , M. Walmsley

When considering particles produced in reactive plasmas, their basic properties, such as refractive index and grain size often need to be known. They can be constrained both ex-situ, e.g., by microscopy, and in-situ by polarimetry, i.e.,…

Plasma Physics · Physics 2022-06-28 Julia Kobus , Andreas Petersen , Franko Greiner , Sebastian Wolf

Multi-band linear polarimetric observations of 125 stars in the region of the cluster NGC 1817 have been carried out intending to study properties of interstellar dust and grains in that direction. The polarization is found to be…

Solar and Stellar Astrophysics · Physics 2020-11-18 Sadhana Singh , Jeewan C. Pandey

Filamentary structures in neutral hydrogen (HI) emission are well aligned with the interstellar magnetic field, so HI emission morphology can be used to construct templates that strongly correlate with measurements of polarized thermal dust…

Astrophysics of Galaxies · Physics 2024-09-04 George Halal , Susan E. Clark , Ari Cukierman , Dominic Beck , Chao-Lin Kuo

Galactic dust emission is polarized at unexpectedly high levels, as revealed by Planck. The origin of the observed $\simeq 20\%$ polarization fractions can be identified by characterizing the properties of optical starlight polarization in…

Astrophysics of Galaxies · Physics 2019-04-17 G. V. Panopoulou , B. S. Hensley , R. Skalidis , D. Blinov , K. Tassis

It is well known that aligned, aspherical dust grains emit polarized radiation and that the degree of polarization depends on the angle $\psi$ between the interstellar magnetic field and the line of sight. However, anisotropy of the dust…

Astrophysics of Galaxies · Physics 2020-01-08 Brandon S. Hensley , Cheng Zhang , James J. Bock

In this paper we have studied the chemistry of C, H, N, O, and S compounds corresponding to ions of masses <=40 amu in the inner coma of the comet 1P/Halley. The production rates, loss rates, and ion mass densities are calculated using the…

Astrophysics · Physics 2009-11-11 S. A. Haider , Anil Bhardwaj

HH 30 is a T Tauri star. In this thesis photometric and polarimetric observations through the source are reported. The observations were carried out using the 84cm telescope of the National Observatory of Mexico (OAN-SPM). This thesis also…

Earth and Planetary Astrophysics · Physics 2015-06-03 Maria Carolina Duran-Rojas

Dust polarization depends on the physical and mechanical properties of dust, as well as the properties of local environments. To understand how dust polarization varies with grain mechanical properties and the local environment, in this…

Astrophysics of Galaxies · Physics 2020-06-17 Hyeseung Lee , Thiem Hoang , Ngan Le , Jungyeon Cho

Assuming a hydrostatic equilibrium in an HI cloud, the joint Poisson's equation is set up and numerically solved to calculate the expected HI distribution. Unlike previous studies, the cloud is considered to be non-isothermal, and an {\it…

Astrophysics of Galaxies · Physics 2018-08-15 Narendra Nath Patra

Recent observations with dust detectors on board the interplanetary spacecraft Ulysses and Galileo have recorded a substantial flux of large interstellar grains with radii between 0.25 and 2.0 mu entering the solar system from the local…

Astrophysics · Physics 2009-11-06 Adolf N. Witt , Randall K. Smith , Eli Dwek

Polarization-mode observations from the Atacama Large Millimeter/submillimeter Array (ALMA) are powerful tools for studying the dust grain populations in circumstellar disks. Many sources exhibit polarization signatures consistent with…

We report optical imaging, optical and near-infrared polarimetry, and Spitzer mid-infrared spectroscopy of comet C/2007 N3 (Lulin). Polarimetric observations were obtained in R (0.676 micron) at phase angles from 0.44 degrees to 21 degrees…

We calculate the degree of linear polarization of radiation from stars having planets that may not be resolved spatially. We assume single scattering by water and silicate particulates in the planetary atmosphere. The dilution of the…

Astrophysics · Physics 2009-11-13 Sujan Sengupta , Malay Maiti

While scattering of light by atoms and molecules yields large amount of polarization at the B-band of both T- and L-dwarfs, scattering by dust grains in cloudy atmosphere of L-dwarfs gives rise to significant polarization at the far-optical…

Solar and Stellar Astrophysics · Physics 2016-10-04 Sujan Sengupta