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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

Measurements of the stellar coronal magnetic field are of great importance in understanding the stellar magnetic activity, yet the measurements have been extremely difficult. Recent studies proposed a new method of magnetic field…

Solar and Stellar Astrophysics · Physics 2022-10-26 Xianyu Liu , Hui Tian , Yajie Chen , Wenxian Li , Meng Jin , Xianyong Bai , Zihao Yang

We have investigated the grain alignment and dust properties towards the direction of the cluster NGC 2345 using the multi-band optical polarimetric observations. For the majority of the stars, the observed polarization is found to be due…

Astrophysics of Galaxies · Physics 2022-06-01 Sadhana Singh , Jeewan C. Pandey , Thiem Hoang

In this analysis we illustrate how the relatively new emission mechanism known as spinning dust can be used to characterize dust grains in the interstellar medium. We demonstrate this by using spinning dust emission observations to…

Coagulation in the dense interstellar medium (ISM) is an important process that determines the size of the largest grains. We use submillimetre galaxies (SMGs) as laboratories of grain coagulation, since some of them host the densest ISM on…

Astrophysics of Galaxies · Physics 2023-10-09 Hiroyuki Hirashita , Chian-Chou Chen

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

We compiled the polarimetric data for a sample of lines of sight with known abundances of Mg, Si, and Fe. We correlated the degree of interstellar polarization $P$ and polarization efficiency (the ratio of $P$ to the colour excess $E(B-V)$…

Astrophysics of Galaxies · Physics 2015-06-04 N. V. Voshchinnikov , Th. Henning , M. S. Prokopjeva , H. K. Das

Recent experiments have highlighted the intrinsic magnetic anisotropy in coil-coil diblock copolymers, specifically in poly(styrene-b-4-vinylpyridine) (PS-b-P4VP), that enables magnetic field alignment at field strengths of a few tesla. We…

We present a study of the correlation between the direction of the symmetry axis of the circumstellar material around intermediate mass young stellar objects and that of the interstellar magnetic field. We use CCD polarimetric data on 100…

Astrophysics of Galaxies · Physics 2011-02-11 Claudia V. Rodrigues , Marilia J. Sartori , Jane Gregorio-Hetem , A. Mario Magalhaes

Submillimeter dust polarization measurements of a sample of 50 star-forming regions, observed with the SMA and the CSO covering pc-scale clouds to mpc-scale cores, are analyzed in order to quantify the magnetic field importance. The…

Gravitational microlensing has become a mature technique for discovering small gravitational lenses in the Universe which are otherwise beyond our detection limits. Similarly, plasma microlensing can help us explore cosmic plasma lenses.…

Astrophysics of Galaxies · Physics 2021-09-28 Xun Shi , Zhu Xu

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

Interstellar grains span a wide range of sizes from a few angstroms to a few micrometers. The presence of nanometer-sized or smaller particles in the interstellar medium is indicated directly by the interstellar far ultraviolet (UV)…

Astrophysics · Physics 2007-05-23 Aigen Li

Very-high energy observations of blazars can be used to constrain the strength of the intergalactic magnetic field. A simplifying assumption which is often made is that of a magnetic field of constant strength composed by randomly oriented…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Chiara Caprini , Stefano Gabici

Magnetic fields pervade in the interstellar medium (ISM) and are believed to be important in the process of star formation, yet probing magnetic fields in star formation regions is challenging. We propose a new method to use Faraday…

Astrophysics of Galaxies · Physics 2018-06-27 M. Tahani , R. Plume , J. C. Brown , J. Kainulainen

The quantization of energy levels in very nanoparticles suppresses dissipative processes that convert grain rotational kinetic energy into heat. For grains small enough to have GHz rotation rates, the suppression of dissipation can be…

Astrophysics of Galaxies · Physics 2017-04-05 B. T. Draine , Brandon S. Hensley

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

The magnetization of an ensemble of isolated lead grains of sizes ranging from below 6 nm to 1000 nm is measured. A sharp disappearance of Meissner effect with lowering of the grain size is observed for the smaller grains. This is a direct…

Superconductivity · Physics 2009-11-07 S. Reich , G. Leitus , R. Popovitz-Biro , M. Schechter

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

A model was developed for the excitation of the UIBs by H atom impacts in the Interstellar Medium. It builds upon the fact that, in the presence of far UV radiation and hydrocarbon grains, the hydrogen gas will be partially dissociated and…

Astrophysics of Galaxies · Physics 2015-05-30 Renaud Papoular