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We study the mass spectrum of sub-structures in the Perseus Molecular Cloud Complex traced by 13CO (1-0), finding that $dN/dM\propto M^{-2.4}$ for the standard Clumpfind parameters. This result does not agree with the classical…

Astrophysics of Galaxies · Physics 2009-07-22 Jaime E. Pineda , Erik W. Rosolowsky , Alyssa A. Goodman

The reliability of modeling the far-IR continuum to 13CO J=1-0 spectral line ratios applied to the Orion clouds (Wall 2006) is tested by applying the models to simulated data. The two-component models are found to give the dust-gas…

Astrophysics · Physics 2008-11-26 W. F. Wall

At radio wavelengths, scattering in the interstellar medium distorts the appearance of astronomical sources. Averaged over a scattering ensemble, the result is a blurred image of the source. However, Narayan & Goodman (1989) and Goodman &…

Instrumentation and Methods for Astrophysics · Physics 2016-01-19 Michael D. Johnson , Carl R. Gwinn

We develop the formalism required to interpret, within a CDM framework, the angular clustering of sources in a deep radio survey. The effect of nonlinear evolution of density perturbations is discussed as is the effect of the assumed…

Astrophysics · Physics 2009-10-30 C. M. Cress , M. Kamionkowski

In this contribution, I discuss some basic techniques that can be used to simulate radiative transfer through porous media. As specific examples, I consider scattering transfer through a clumped slab, and X-ray emission line formation in a…

Astrophysics · Physics 2007-09-07 Rich Townsend

Mass-loss rates currently in use for hot, massive stars have recently been seriously questioned, mainly because of the effects of wind clumping. We investigate the impact of clumping on diagnostic ultraviolet resonance and optical…

Solar and Stellar Astrophysics · Physics 2015-05-27 J. O. Sundqvist , J. Puls , A. Feldmeier , S. P. Owocki

The presence of resonances modifies the passage of light or of electrons through a disordered medium. We generalize random matrix theory to account for this effect. Using supersymmetry, we calculate analytically the mean density of states,…

Disordered Systems and Neural Networks · Physics 2009-10-31 B. Elattari , V. Kagalovsky , H. A. Weidenmueller

In this paper we re-analyse the amplification process of broadband continuum radiation by astronomical masers in one-dimensional case. The basic equations appropriate for the scalar maser and the random nature of the maser radiation field…

Astrophysics of Galaxies · Physics 2015-05-13 Dinh-V-Trung

Statistical properties of coherent radiation propagating in a quasi - 1D random media is studied in the framework of random matrix theory. Distribution functions for the total transmission coefficient and the angular transmission…

Condensed Matter · Physics 2009-10-28 Eugene Kogan , Moshe Kaveh

[Abridged] We develop and benchmark a fast and easy-to-use effective-opacity formalism for line and continuum radiative transfer in an accelerating two-component clumpy medium. The formalism bridges the limits of optically thin and thick…

Solar and Stellar Astrophysics · Physics 2015-06-19 J. O. Sundqvist , J. Puls , S. P. Owocki

We report a detailed and systematic numerical study of wave propagation through a coherently amplifying random one-dimensional medium. The coherent amplification is modeled by introducing a uniform imaginary part in the site energies of the…

Disordered Systems and Neural Networks · Physics 2009-10-30 Sandeep K. Joshi , A. M. Jayannavar

We study the standard spectral line radiative transfer equation for media consisting of resonant atoms and non-resonant components (the dust grains and the atoms without considered spectral transition). Our goal is to study the intensity…

Astrophysics of Galaxies · Physics 2017-06-21 N. A. Silant'ev , G. A. Alekseeva , V. V. Novikov

We study line driven stellar winds using time-dependent radiation hydrodynamics where the continuum radiation couples to the gas via either a scattering or absorption opacity and there is an additional radiation force due to spectral lines…

Solar and Stellar Astrophysics · Physics 2023-11-30 Sergei Dyda , Shane W. Davis

A detailed study of the absorbing molecular clouds towards the radio source PKS1413+135, at a redshift z=0.247, is reported. Physical conditions are derived for the molecular gas in the frame work of two models: a homogeneous multicomponent…

Astrophysics · Physics 2007-05-23 Tommy Wiklind , Francoise Combes

Power distribution grids are exploited by Power Line Communication (PLC) technology to convey high frequency data signals. The natural conformation of such power line networks causes a relevant part of the high frequency signals traveling…

Physics and Society · Physics 2017-09-29 Davide Righini , Federico Passerini , Andrea M. Tonello

The propagation of SH waves in a solid containing a screen of line-like scatterers is investigated. When the scatterers are uniformly distributed, the amplitudes of the coherent waves inside and outside the screen are evaluated in closed…

Classical Physics · Physics 2009-03-31 Yves C. Angel , Christophe Aristégui , Mihai Caleap

Calculations of frequency spectra for organic molecular crystals taking various defects in their structure into account are carried out. It is shown how the presence of the vacancies, orientation disorder, and surface presence affects…

Soft Condensed Matter · Physics 2007-09-19 M. A. Korshunov

We consider the propagation of cosmic rays in turbulent magnetic fields. We use the models of magnetohydrodynamic turbulence that were tested in numerical simulations, in which the turbulence is injected on large scale and cascades to small…

Astrophysics · Physics 2009-11-13 Huirong Yan , A. Lazarian

It is known that scattering of radiation by circumstellar dust can strongly change the line profiles in stellar spectra. This hampers the analysis of spectral lines originating in the emitting regions of heavily obscured young stars. To…

Solar and Stellar Astrophysics · Physics 2015-06-05 V. P. Grinin , L. V. Tambovtseva , G. Weigelt

We analyse the superluminal propagation of narrow-band pulses at resonances in dissipative media. The output waveform is an attenuated, undistorted, time-advanced version of the input which can be interpreted as the result of the…

Optics · Physics 2008-05-29 P. Chamorro-Posada , F. J. Fraile-Pelaez