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We extend and investigate the spheroidal model of interstellar dust grains used to simultaneously interpret the observed interstellar extinction and polarization curves. We compare our model with similar models recently suggested by other…

Astrophysics of Galaxies · Physics 2015-05-14 H. K. Das , N. V. Voshchinnikov , V. B. Il'in

Polarized extinction and emission from dust in the interstellar medium (ISM) are hard to interpret, as they have a complex dependence on dust optical properties, grain alignment and magnetic field orientation. This is particularly true in…

Astrophysics of Galaxies · Physics 2017-05-24 Lapo Fanciullo , Vincent Guillet , François Boulanger , Anthony Jones

The properties of polarization in scattered light by aligned ellipsoidal grains are investigated with the Fredholm integral equation method (FIM) and the T-matrix method (Tmat), and the results are applied to the observed circular…

Astrophysics of Galaxies · Physics 2010-01-15 Masafumi Matsumura , Pierre Bastien

We analyze the wavelength dependence of the far-infrared polarization fraction toward the OMC-1 star forming region using observations from HAWC+/SOFIA at 53, 89, 154, and 214 $\mu$m. We find that the shape of the far-infrared polarization…

Continuum polarization over the UV-to-microwave range is due to dichroic extinction (or emission) by asymmetric, aligned dust grains. Because of both grain alignment and scattering physics, the wavelength dependence of the polarization,…

We present polarisation spectra of seven stars in the lines-of-sight towards the Sco OB1 association. Our spectra were obtained within the framework of the Large Interstellar Polarization Survey carried out with the FORS instrument of the…

Astrophysics of Galaxies · Physics 2017-12-20 R. Siebenmorgen , N. V. Voshchinnikov , S. Bagnulo , Cox N. L. J.

Thermal dust continuum polarimetry is a powerful indirect probe of magnetic field geometry in dense molecular clouds while at the same time providing information on the alignment of dust grains with the magnetic field. The leading theory of…

The wavelength dependence of interstellar polarization due to dust in M31 has been observed along four sightlines. Only one sightline had been measured previously.The globular clusters, S78, S150, S233 and Baade 327 were used as point…

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

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

Dust in the diffuse interstellar medium remains incompletely understood with regard to the structure, composition, size distribution, and alignment properties of the grains. Joint observations of reddening, starlight polarisation spectra,…

Astrophysics of Galaxies · Physics 2026-05-27 Ralf Siebenmorgen , Stefano Bagnulo , Lapo Fanciullo , Thomas Vannieuwenhuyse , Vincent Guillet

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…

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

Recent photometric and polarimetric observations of type Ia supernovae (SNe Ia) show unusually low total-to-selective extinction ratio ($R_{V}<2$) and wavelength of maximum polarization ($\lambda_{max}<0.4\mu m$) for several SNe Ia, which…

Astrophysics of Galaxies · Physics 2017-03-08 Thiem Hoang

Interstellar polarization in the optical/infrared has long been known to be due to asymmetrical dust grains aligned with the magnetic field and can potentially provide a resource effective way to probe both the topology and strength of the…

Astrophysics of Galaxies · Physics 2012-08-23 B. -G. Andersson

Grain alignment theory has reached the stage where quantitative predictions of the degree of alignment and its variations with optical depth are possible. With the goal of studying the effect of clumpiness on the sub-millimeter and far…

Astrophysics · Physics 2011-02-11 T. J. Bethell , A. Chepurnov , A. Lazarian , J. Kim

The results of a near-infrared (J H K LP) imaging linear polarimetry survey of 20 young stellar objects (YSOs) in rho Ophiuchi are presented. The majority of the sources are unresolved, with K-band polarizations, P_K < 6 per cent. Several…

Astrophysics · Physics 2009-11-13 A. F. Beckford , P. W. Lucas , A. C. Chrysostomou , T. M. Gledhill

Atacama Large Millimeter/Submillimeter Array (ALMA) has revolutionized the field of dust polarization in protoplanetary disks across multiple wavelengths. Previous observations and empirical modeling suggested multiple mechanisms of dust…

Solar and Stellar Astrophysics · Physics 2024-07-30 Nguyen Tat Thang , Pham Ngoc Diep , Thiem Hoang , Le Ngoc Tram , Nguyen Bich Ngoc , Nguyen Thi Phuong , Bao Truong

By radiation transfer models with a realistic power spectra of the projected density distributions, we show that the optical properties of grains are poorly constrained by observations of reflection nebulae. The ISM is known to be…

Astrophysics · Physics 2009-11-07 John S. Mathis , Barbara A. Whitney , Kenneth Wood

The recent detection of interstellar polarization in the solid CO feature near 4.67 micron shows that CO-mantled grains can be aligned in cold molecular clouds. These observations conflict with a theory of grain alignment which attributes…

Astrophysics · Physics 2015-06-24 A. Lazarian , W. G. Roberge