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We expand our study on the dispersion of polarization angles in molecular clouds. We show how the effect of signal integration through the thickness of the cloud as well as across the area subtended by the telescope beam inherent to dust…

Astrophysics of Galaxies · Physics 2014-11-20 Martin Houde , John E. Vaillancourt , Roger H. Hildebrand , Shadi Chitsazzadeh , Larry Kirby

We present distribution functions and spatial correlations of the shapes of dark matter halos derived from Hubble Volume simulations of a LambdaCDM universe. We measure both position and velocity shapes within spheres encompassing mean…

Astrophysics · Physics 2008-11-26 S. F. Kasun , A. E. Evrard

At the cloud top level of Venus (65-70 km altitude) the atmosphere rotates 60 times faster than the underlying surface, a phenomenon known as superrotation. Whereas on Venus's dayside the cloud top motions are well determined and Venus…

Earth and Planetary Astrophysics · Physics 2018-02-13 J. Peralta , R. Hueso , A. Sánchez-Lavega , Y. J. Lee , A. García-Muñoz , T. Kouyama , H. Sagawa , T. M. Sato , G. Piccioni , S. Tellmann , T. Imamura , T. Satoh

This paper describes some interesting properties of waves in, and oscillations of, the interstellar medium in the direction normal to the plane of the Galaxy. Our purpose is to examine possible reasons for four observed phenomena: the…

Astrophysics · Physics 2009-10-31 Michael A. Walters , Donald P. cox

As a helicopter descends towards a bed of sand, a high velocity particle laden cloud can form around the helicopter body, a phenomenon known as "brownout", and a consequence of which can potentially be a significant deterioration in…

Fluid Dynamics · Physics 2024-12-24 Stephen Langdon , David J. Needham

Context. Clouds have already been detected in exoplanetary atmospheres. They play crucial roles in a planet's atmosphere and climate and can also create ambiguities in the determination of atmospheric parameters such as trace gas mixing…

Earth and Planetary Astrophysics · Physics 2017-11-22 Loïc Rossi , Daphne Stam

We use numerical simulations of turbulent cluster-forming regions to study the nature of dense filamentary structures in star formation. Using four hydrodynamic and magnetohydrodynamic simulations chosen to match observations, we identify…

Astrophysics of Galaxies · Physics 2015-06-23 Helen Kirk , Ralph Pudritz , Mikhail Klassen , Samantha Pillsworth

The strengths of magnetic fields in interstellar gas clouds are obtained through observations of the circular polarization of spectral line radiation. Irregularities in this magnetic field may be present due to turbulence, waves or perhaps…

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

Curve of growth analysis, applied to the Lyman series absorption ratios deduced in our previous paper, yields a measurement of the logarithmic slope of distribution of \Lya\ clouds in column density $N$. The observed exponential…

Astrophysics · Physics 2009-10-22 William H. Press , George B. Rybicki

The size of dust grains, $a$, is key to the physical and chemical processes in circumstellar disks, but observational constraints of grain size remain challenging. (Sub)millimeter continuum observations often show a percent-level…

In the surface layers of late-type stars, stellar convection is manifested with its typical granulation pattern due to the presence of convective motions. The resulting photospheric up- and downflows leave imprints in the observed spectral…

Solar and Stellar Astrophysics · Physics 2014-05-30 Zazralt Magic , Martin Asplund

Dust polarization orientations in molecular clouds often tend to be close to tangential to the Stokes $I$ dust continuum emission contours. The magnetic field and the emission gradient orientations, therefore, show some correlation. A…

Astrophysics of Galaxies · Physics 2015-06-03 Patrick M. Koch , Ya-Wen Tang , Paul T. P. Ho

We present a method to calculate vertical profiles of particle size distributions in condensation clouds of giant planets and brown dwarfs. The method assumes a balance between turbulent diffusion and sedimentation in horizontally uniform…

Astrophysics · Physics 2009-11-06 Andrew S. Ackerman , Mark S. Marley

We study analytically the development of gravitational instability in an expanding shell having finite thickness. We consider three models for the radial density profile of the shell: (i) an analytic uniform-density model, (ii) a…

Astrophysics of Galaxies · Physics 2015-05-19 Richard Wunsch , James E. Dale , Jan Palous , Anthony P. Whitworth

The optical reflection coefficient of a dielectric medium moving uniformly in the plane spanned by its surface is rigorously calculated using classical electrodynamics and special relativity, and expressed in the Fourier domain, as a…

Meteorologists use shapes and movements of clouds in satellite images as indicators of several major types of severe storms. Satellite imaginary data are in increasingly higher resolution, both spatially and temporally, making it impossible…

Computer Vision and Pattern Recognition · Computer Science 2019-06-26 Xinye Zheng , Jianbo Ye , Yukun Chen , Stephen Wistar , Jia Li , Jose A. Piedra-Fernández , Michael A. Steinberg , James Z. Wang

We present corrections for the change in the apparent scalelengths, central surface brightnesses and axis ratios due to the presence of dust in pure disk galaxies, as a function of inclination, central face-on opacity in the B-band…

Astrophysics · Physics 2009-11-11 C. Möllenhoff , C. C. Popescu , R. J. Tuffs

Slip transfer across grain boundaries was studied in annealed polycrystalline Al foils deformed in uniaxial tension by means of the analysis of the slip traces on the specimen surface. Grain orientations and selected grain boundary…

Materials Science · Physics 2019-05-01 T. R Bieler , R. Alizadeh , M. Peña-Ortega , J. LLorca

The molecular cloud, DR21 Main, is an example of a large-scale gravitational collapse about an axis near the plane of the sky where the collapse is free of major disturbances due to rotation or other effects. Using flux maps, polarimetric…

Astrophysics · Physics 2011-02-11 Larry Kirby

Recent work by Mitra et al. (2014) has shown that in strongly stratified forced two-layer turbulence with helicity and corresponding large-scale dynamo action in the lower layer, a magnetic field occurs in the upper layer in the form of…

Solar and Stellar Astrophysics · Physics 2015-06-03 Sarah Jabbari , Axel Brandenburg , Nathan Kleeorin , Dhrubaditya Mitra , Igor Rogachevskii