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相关论文: On the efficiency of grain alignment in dark cloud…

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We show that grains can be efficiently aligned by interacting with a subsonic gaseous flow. The alignment arises from grains having irregularities that scatter atoms with different efficiency in the right and left directions. The grains…

天体物理学 · 物理学 2009-11-13 Alex Lazarian , Thiem Hoang

Polarized dust emission is a key tracer in the study of interstellar medium and of star formation. The observed polarization, however, is a product of magnetic field structure, dust grain properties and grain alignment efficiency, as well…

We present synthetic dust polarisation maps of 3D magneto-hydrodynamical simulations of molecular clouds before the onset of stellar feedback. The clouds are modelled within the SILCC-Zoom project and are embedded in their galactic…

星系天体物理 · 物理学 2018-10-31 D. Seifried , S. Walch , S. Reissl , J. C. Ibáñez-Mejía

We present 870 $\mu$m ALMA polarization observation toward the Class I\hspace{-.1em}I protoplanetary disk around AS 209, which has concentric, multiple gaps and rings. We successfully detect the polarized emission and find that the…

地球与行星天体物理 · 物理学 2019-09-25 Tomohiro Mori , Akimasa Kataoka , Satoshi Ohashi , Munetake Momose , Takayuki Muto , Hiroshi Nagai , Takashi Tsukagoshi

We develop a comprehensive quantitative description of the cross-section mechanism discovered several years ago by Lazarian. This is one of the processes that determine grain orientation in clouds of suprathermal cosmic dust. The…

天体物理学 · 物理学 2009-11-07 Michael Efroimsky

We use polarimetric observations of two stars (HD29647, HD283809) in the general direction of TMC-1 in the Taurus Dark Cloud to investigate grain properties and cloud structure in this region. We show the data to be consistent with a simple…

天体物理学 · 物理学 2009-10-30 D. W. Messinger , D. C. B. Whittet , W. G. Roberge

We use the PPMAP (Point Process MAPping) algorithm to re-analyse the \textit{Herschel} and SCUBA-2 observations of the L1688 and L1689 sub-regions of the Ophiuchus molecular cloud. PPMAP delivers maps with high resolution (here $14''$,…

星系天体物理 · 物理学 2021-05-12 A. D. P. Howard , A. P. Whitworth , M. J. Griffin , K. A. Marsh , M. W. L. Smith

The motion of diamagnetic dust particles in interstellar magnetic fields is studied numerically with several different sets of parameters. Two types of behavior are observed, depending on the value of the critical number $R$, which is a…

星系天体物理 · 物理学 2018-02-21 Renaud Papoular

The radiative torque (RAT) mechanism is the most promising way of explaining observed polarization arising from aligned grains. We explore the efficiency of the grain alignment by an anisotropic radiation flow for an extensive ensemble of…

星系天体物理 · 物理学 2019-06-26 Joonas Herranen , Alex Lazarian , Thiem Hoang

Dust grains grow their sizes in the interstellar clouds (especially in molecular clouds) by accretion and coagulation. Here we model and test these processes by examining the consistency with the observed variation of the extinction curves…

星系天体物理 · 物理学 2015-06-17 Hiroyuki Hirashita , Nikolai V. Voshchinnikov

We report on polarimetric maps made with HAWC+/SOFIA toward Rho Oph A, the densest portion of the Rho Ophiuchi molecular complex. We employed HAWC+ bands C (89 $\mu$m) and D (154 $\mu$m). The slope of the polarization spectrum was…

Context. Planck observations demonstrated that the grain alignment efficiency is almost constant in the diffuse ISM. Aims. We test if the Radiative Torque (RAT) theory is compatible with observational constraints on grain alignment.…

天体物理仪器与方法 · 物理学 2020-08-26 Stefan Reissl , Vincent Guillet , Robert Brauer , François Levrier , François Boulanger , Ralf S. Klessen

Dust polarization, which comes from the alignment of aspherical grains to magnetic fields, has been widely employed to study the interstellar medium (ISM) dust properties. The wavelength dependence of the degree of optical polarization,…

星系天体物理 · 物理学 2024-11-15 Raphael Skalidis

We have analyzed the properties of dust in the high galactic latitude translucent cloud Lynds 1780 using ISOPHOT maps at 100 and 200 micrometers and raster scans at 60, 80, 100, 120, 150 and 200 micrometers. In far-infrared (FIR) emission,…

天体物理学 · 物理学 2009-11-11 M. Ridderstad , M. Juvela , K. Lehtinen , D. Lemke , T. Liljestrom

Telescopes are now able to resolve dust polarization across circumstellar disks at multiple wavelengths, allowing the study of the polarization spectrum. Most disks show clear evidence of dust scattering through their unidirectional…

太阳与恒星天体物理 · 物理学 2022-04-27 Zhe-Yu Daniel Lin , Zhi-Yun Li , Haifeng Yang , Ian Stephens , Leslie Looney , Rachel Harrison , Manuel Fernández-López

(abridged) The polarized thermal radiation at far infrared and submillimeter wavelengths from dust grains in interstellar clouds with irregular magnetic fields is simulated. We show that the polarization properties of quiescent clouds and…

天体物理学 · 物理学 2009-11-10 D. S. Wiebe , W. D. Watson

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…

天体物理学 · 物理学 2008-11-26 Joseph C. Weingartner

Polarization of starlight induced by dust grains aligned with the magnetic field (hereafter B-field) is widely used to measure the two-dimensional B-fields projected onto the plane-of-sky. Here, we introduce a new method to infer…

星系天体物理 · 物理学 2025-02-04 Bao Truong , Thiem Hoang

Motivated by a recent study by Lazarian and Draine, which showed that a high degree of grain alignment of the paramagnetic dust is achievable if the rates of internal relaxation are controlled by the Barnett relaxation process, we undertake…

天体物理学 · 物理学 2009-10-31 A. Lazarian , M. Efroimsky

We have computed the size distribution of silicate grains in the outer radiative region of the envelope of a protoplanet evolving according to the scenario of Pollack et al. (1996). Our computation includes grain growth due to Brownian…

天体物理学 · 物理学 2009-11-13 Naor Movshovitz , Morris Podolak