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Unified schemes of active galactic nuclei (AGN) require an obscuring dusty torus around the central source, giving rise to type 1 line spectrum for pole-on viewing and type 2 characteristics in edge-on sources. Infrared radiation at its…

Astrophysics · Physics 2007-05-23 Moshe Elitzur , Maia Nenkova , Zeljko Ivezic

We consider the collective scattering by a cloud of $N$ two-level atoms driven by an uniform radiation field. Dense atomic clouds can be described by a continuous density and the problem reduces to deriving the spectrum of the atom-atom…

Optics · Physics 2015-03-31 Romain Bachelard , Nicola Piovella , Philippe Courteille

By studying the temperature-dependent behavior of electron thermal conductivity (k) in a 3.2 nm-thin film, we quantify the extremely confined defect-electron scattering and reveal the intrinsic phonon-electron scattering that is shared by…

Mesoscale and Nanoscale Physics · Physics 2015-01-16 Zhe Cheng , Zaoli Xu , Shen Xu , Xinwei Wang

Some bright cD galaxies in cluster cooling flows have Thomson optical depths exceeding 0.01. A few percent of their luminosity is scattered and appears as diffuse polarized emission. We calculate the scattering process for different…

Astrophysics · Physics 2009-10-22 B. W. Murphy , D. F. Chernoff

It is known that the millimeter dust thermal emission of protoplanetary disks is affected by scattering, such that for optically thick disks the emission decreases with respect to the pure absorption case and the spectral indices can reach…

Earth and Planetary Astrophysics · Physics 2020-04-15 Anibal Sierra , Susana Lizano

We examine the cloud structure around the Planck detections in 71 fields observed with the Herschel SPIRE instrument. We wish to determine the general physical characteristics of the fields and to examine the morphology of the clouds where…

Symbiotic binaries are comprised of nebulae, whose densest portions have electron concentrations of 1E+8 - 1E+12 cm-3 and extend to a few AU. They are optically thick enough to cause a measurable effect of the scattering of photons on free…

Solar and Stellar Astrophysics · Physics 2015-06-11 M. Sekeras , A. Skopal

Based on the quantum electrodynamics, we present a generic formalism of the polarization for beamed monochromatic photons scattered by electrons in any spectral distribution. The formulae reduce to the components of the Fano matrix when…

High Energy Astrophysical Phenomena · Physics 2014-11-07 Zhe Chang , Yunguo Jiang , Hai-Nan Lin

We present an investigation on effect of the ion-neutral (or ambipolar) diffusion heating rate on thermal phases of a molecular cloud. We use the modeling of ambipolar diffusion with two-fluid smoothed particle hydrodynamics, as discussed…

Astrophysics · Physics 2008-04-29 M. Nejad-Asghar , D. Molteni

The radiative cooling of optically thin gaseous regions and the formation of a two-phase medium and of cold gas clouds with a clumpy substructure is investigated. In optically thin clouds, the growth rate of small isobaric density…

Astrophysics · Physics 2009-10-31 A. Burkert , D. N. C. Lin

A general theoretical framework is developed for interpreting spectropolarimetric observations of optically thin emission line scattering from small dust particles. Spatially integrated and spatially resolved line profiles of both scattered…

Astrophysics · Physics 2009-10-22 W. J. Henney

Ordinary metallic photonic crystals (PCs) have photonic band gaps in which the density of states (DOS) is strongly modified. Thermal emission of photons can be suppressed and enhanced accordingly. We consider the thermal emission…

Optics · Physics 2007-05-23 Jones T. K. Wan , C. T. Chan

Transmission spectra of exoplanetary atmospheres have been used to infer the presence of clouds/hazes. Such inferences are typically based on spectral slopes in the optical deviant from gaseous Rayleigh scattering or low-amplitude spectral…

Earth and Planetary Astrophysics · Physics 2017-08-31 Arazi Pinhas , Nikku Madhusudhan

The simple 3-D radiative transfer model in the atmosphere of the Earth is built for numerical comparison of direct solar radiation and limb scattering background at the definite layer during the deep twilight period at the middle and upper…

Atmospheric and Oceanic Physics · Physics 2025-09-05 Oleg S. Ugolnikov

Using a general circulation model (GCM), we investigate trends in simulated hot Jupiter atmospheres for a range of irradiation temperatures (1,500 - 4,000 K), surface gravities (10 and 40 m s-2), and cloud conditions. Our models include…

Earth and Planetary Astrophysics · Physics 2021-02-24 Michael T. Roman , Eliza M. -R. Kempton , Emily Rauscher , Caleb K. Harada , Jacob L. Bean , Kevin B. Stevenson

In this paper, we study cooperative scattering of low intensity light by a cloud of N two-level systems. We include the incident laser field driving these two-level systems and compute the radiation pressure force on the center of mass of…

Atomic Physics · Physics 2012-01-17 Tom Bienaime , Marco Petruzzo , Daniele Bigerni , Nicola Piovella , Robin Kaiser

A number of studies have shown that the visibility of scattered broad emission lines in Seyfert 2 galaxies is strongly dependent on the IRAS f_60/f_25 flux ratio, where those Seyfert 2s with `warm' IRAS colours show polarised broad line…

Astrophysics · Physics 2009-11-07 S. L. Lumsden , D. M. Alexander

Understanding the optical properties of exoplanet cloud particles is a top priority. Many cloud condensates form as nonspherical particles and their optical properties can be very different from those of spheres. In this study, we focus on…

Earth and Planetary Astrophysics · Physics 2025-07-09 Colin D. Hamill , Alexandria V. Johnson , Matt Lodge , Peter Gao , Rowan Nag , Natasha Batalha , Duncan A. Christie , Hannah R. Wakeford

Scattering and absorption properties at optical and ultraviolet wavelengths are calculated for an interstellar dust model consisting of carbonaceous grains and amorphous silicate grains. Polarization as a function of scattering angle is…

Astrophysics · Physics 2011-05-05 B. T. Draine

The irradiation of a dilute cloud of cold atoms with a coherent light field produces a random intensity distribution known as laser speckle. Its statistical fluctuations contain information about the mesoscopic scattering processes at work…

Disordered Systems and Neural Networks · Physics 2016-08-08 Cord A. Müller , Benoît Grémaud , Christian Miniatura