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Related papers: 2n-Stream Thermal Emissions from Clouds

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For 2n-stream radiation transfer theory, a stack of m clouds can be represented as an equivalent cloud. Individual clouds, indexed by c = 1, 2, 3, ..., m are characterized by 2n x 2n scattering matrices S^{c}, that describe how the cloud…

Atmospheric and Oceanic Physics · Physics 2023-10-17 W. A. van Wijngaarden , W. Happer

We show how to use matrix methods of quantum mechanics to efficiently and accurately calculate axially symmetric radiation transfer in clouds, with conservative scattering of arbitrary anisotropy. Analyses of conservative scattering, where…

Atmospheric and Oceanic Physics · Physics 2022-07-11 W. A. van Wijngaarden , W. Happer

The early part of a supernova (SN) light-curve is dominated by radiation escaping from the expanding shock-heated progenitor envelope. For polytropic Hydrogen envelopes, the properties of the emitted radiation are described by simple…

High Energy Astrophysical Phenomena · Physics 2017-04-12 Nir Sapir , Eli Waxman

(abridged) We calculate near-infrared thermal emission spectra using a doubling-adding radiative transfer code, which includes scattering by clouds and haze. Initial temperature profiles and cloud optical depths are taken from the…

Earth and Planetary Astrophysics · Physics 2011-08-08 R. J. de Kok , Ch. Helling , D. M. Stam , P. Woitke , S. Witte

The central galaxies of some clusters can be strong emitters in the Ly$\alpha$ and H$\alpha$ lines. This emission may arise either from the cool/warm gas located in the cool core of the cluster or from the bright AGN within the central…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-13 S. Khedekar , E. Churazov , S. Sazonov , R. Sunyaev , E. Emsellem

We study the effect of a weakly driven atomic cloud's polarization distribution on its photon scattering lineshape. In doing this, we find three distinct polarization regimes. First, for dilute clouds, the polarization magnitude is…

Atomic Physics · Physics 2020-01-15 F. Robicheaux , R. T. Sutherland

Direct imaging has paved the way for atmospheric characterization of young and self-luminous gas giants. Scattering in a horizontally-inhomogeneous atmosphere causes the disk-integrated polarization of the thermal radiation to be linearly…

Earth and Planetary Astrophysics · Physics 2018-11-09 Tomas Stolker , Michiel Min , Daphne M. Stam , Paul Mollière , Carsten Dominik , Rens Waters

Planets can emit polarized thermal radiation, just like brown dwarfs. We present calculated thermal polarization signals from hot exoplanets, using an advanced radiative transfer code that fully includes all orders of scattering by gaseous…

Earth and Planetary Astrophysics · Physics 2015-05-30 R. J. de Kok , D. M. Stam , T. Karalidi

We assume a distribution of clouds optically thick for electron scattering (OTCM) which are moderately optically thin for absorption and we consider them as a model of the mean quasar spectrum of Laor et al. (1997). We show that the model…

Astrophysics · Physics 2007-05-23 B. Czerny , A. -M. Dumont

A cloud of cold N two-level atoms driven by a resonant laser beam shows cooperative effects both in the scattered radiation field and in the radiation pressure force acting on the cloud center-of-mass. The induced dipoles synchronize and…

Atomic Physics · Physics 2013-02-05 Tom Bienaime , Romain Bachelard , Nicola Piovella , Robin Kaiser

We discuss the radiative transfer theory for translucent clouds illuminated by an extended background source. First we derive a rigorous solution based on the assumption that multiple scattering produce an isotropic flux. Then we derive a…

Solar and Stellar Astrophysics · Physics 2017-05-10 Davide Biganzoli , Marco Potenza , Massimo Robberto

Observational studies of exoplanets are suggestive of a ubiquitous presence of clouds. The current modelling techniques used in emission to account for the clouds tend to require prior knowledge of the cloud condensing species and often do…

Earth and Planetary Astrophysics · Physics 2021-07-07 Jake Taylor , Vivien Parmentier , Michael R. Line , Elspeth K. H. Lee , Patrick G. J. Irwin , Suzanne Aigrain

When a cold atomic gas is illuminated by a quasi-resonant laser beam, light-induced dipole-dipole correlations make the scattering of light a cooperative process. Once a fluid description is adopted for the atoms, many scattering properties…

Optics · Physics 2013-10-23 N. Piovella , R. Bachelard , Ph. W. Courteille

Emission spectroscopy is an invaluable tool for probing the atmospheres of brown dwarfs and exoplanets, but interpretations based on flux spectra alone often suffer from degeneracies among temperature structure, chemical composition, and…

Earth and Planetary Astrophysics · Physics 2025-12-16 Fei Wang , Yuka Fujii , Ben Burningham , Jinping He

We have calculated the radiation field, dust grain temperatures, and far infrared emissivity of numerical models of turbulent molecular clouds. When compared to a uniform cloud of the same mean optical depth, most of the volume inside the…

Astrophysics · Physics 2009-11-10 Thomas Bethell , Ellen Zweibel , Fabian Heitsch , J. S. Mathis

We use 2n streams, where n is an integer, of axially symmetric radiation to solve the equation of transfer for a layered medium. This is a generalization of Schuster's classic 2 stream model. As is well known, using only the first 2n…

Atmospheric and Oceanic Physics · Physics 2022-06-03 W. A. van Wijngaarden , W. Happer

The primary radiation generated in the central continuum-forming region of Active Galactic Nuclei can be reprocessed by very dense, small-scale clouds that are optically-thin to Thomson scattering. In spite of the extreme conditions…

Astrophysics · Physics 2015-06-24 Z. Kuncic , A. Celotti , M. J. Rees

The controversy regarding the precise nature of the high-temperature phase of 1T-TiSe2 lasts for decades. It has intensified in recent times when new evidence for the excitonic origin of the low-temperature charge-density wave state started…

[abridged] We investigate the effects of various AGN scattering region geometries on the polarized flux. We introduce a new, publicly available Monte Carlo radiative transfer code, Stokes, which models polarization induced by scattering off…

Astrophysics · Physics 2011-01-31 Rene W. Goosmann , C. Martin Gaskell

It is shown that homogeneous line-broadening in a diffuse cold atom cloud is proportional to the resonant optical depth of the cloud. Further, it is demonstrated how the strong directionality of the coherent interactions causes the cloud's…

Atomic Physics · Physics 2016-09-21 R. T. Sutherland , Francis Robicheaux
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