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Emission lines in X-ray spectra of clusters of galaxies reveal the presence of heavy elements in the diffuse hot plasma (the Intra Cluster Medium, or ICM) in virial equilibrium in the dark matter potential well. The relatively simple…

Astrophysics · Physics 2008-11-26 Paolo Tozzi

We consider the effects of radio-wave scattering by cool ionized clumps ($T\sim 10^4\,$K) in circumgalactic media (CGM). The existence of such clumps are inferred from intervening quasar absorption systems, but have long been something of a…

Astrophysics of Galaxies · Physics 2018-12-19 H. K. Vedantham , E. S. Phinney

[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

Filamentary structures are often identified in column density maps of molecular clouds, and appear to be important for both low- and high-mass star formation. Theoretically, these structures are expected to form in regions where the…

Astrophysics of Galaxies · Physics 2023-05-03 F. D. Priestley , D. Arzoumanian , A. P. Whitworth

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

Filamentary structures are ubiquitous in observations of real molecular clouds, and also in simulations of turbulent, self-gravitating gas. However, making comparisons between observations and simulations is complicated by the difficulty of…

Astrophysics of Galaxies · Physics 2020-10-14 F. D. Priestley , A. P. Whitworth

We present constrained radiative transfer calculations of Lyman Alpha (Lya) photons propagating through clumpy, dusty, large scale outflows, and explore whether we can quantitatively explain the Lya halos that have been observed around…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Mark Dijkstra , Roban Hultman Kramer

Line emission is strongly dependent on the local environmental conditions in which the emitting tracers reside. In this work, we focus on modelling the CO emission from simulated giant molecular clouds (GMCs), and study the variations in…

Astrophysics of Galaxies · Physics 2018-02-07 Camilo H. Peñaloza , Paul C. Clark , Simon C. O. Glover , Ralf S. Klessen

The effect of scattering processes in the continuum on the formation of spectral lines in a static atmosphere with an arbitrary distribution of the internal energy sources is investigated using Ambartsumian's principle of invariance.…

Astrophysics · Physics 2009-10-31 G. Israelian

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

Possible observational consequences of dark matter in the Galaxy in the form of dense molecular gas clouds - clumpuscules of masses $M_c\sim 10^{-3} \msun$ and radii $R_c\sim 3\times 10^{13}$ cm - are considered. Recent models of the…

Astrophysics · Physics 2007-05-23 Yu. A. Shchekinov

Curvature radiation is a natural candidate for the emission mechanism of FRB. However, FRB spectra have structure with $\Delta \nu/\nu \sim \text{0.03--0.2}$, inconsistent with the very smooth spectrum of curvature radiation. Although this…

High Energy Astrophysical Phenomena · Physics 2018-09-07 J. I. Katz

This paper considers scattering screens that have arbitrary spatial variations of scattering strength transverse to the line of sight, including screens that are spatially well confined, such as disks and filaments. We calculate the…

Astrophysics · Physics 2009-10-31 J. M. Cordes , T. Joseph W. Lazio

We use detailed numerical simulations of the coupled chemical, thermal and dynamical evolution of the gas in a turbulent molecular cloud to study the usefulness of the [CI] 609 micron and 370 micron fine structure emission lines as tracers…

Astrophysics of Galaxies · Physics 2015-06-19 Simon C. O. Glover , Paul C. Clark , Milica Micic , Faviola Molina

We investigate the wavelength-dependent intensity and reverberation properties of the UV-optical diffuse continuum emission expected from broad emission line gas. The locally optimally emitting clouds picture is adopted, with the cloud…

Astrophysics · Physics 2009-11-06 Kirk T. Korista , Michael R. Goad

The narrow line region of active galaxies is formed by gas clouds surrounded by a diluted gas. Standard one-dimensional photoionization models are usually used to model this region in order to reproduce the observed emission lines. Since…

Astrophysics · Physics 2009-11-07 Lucimara P. Martins , Sueli M. Viegas , Ruth Gruenwald

While very often a hot intergalactic medium (IGM) is optically thin to continuum radiation, the optical depth in resonant lines can be of order unity or larger. Resonant scattering in the brightest X-ray emission lines can cause distortions…

High Energy Astrophysical Phenomena · Physics 2015-05-19 E. Churazov , I. Zhuravleva , S. Sazonov , R. Sunyaev

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

In the second paper of the series, we have modeled low frequency carbon radio recombination lines (CRRL) from the interstellar medium. Anticipating the LOw Frequency ARray (LOFAR) survey of Galactic CRRLs, we focus our study on the physical…

Astrophysics of Galaxies · Physics 2017-03-22 F. Salgado , L. K. Morabito , J. B. R. Oonk , P. Salas , M. C. Toribio , H. J. A. Rottgering , A. G. G. M. Tielens

We study light curves and the spectral broadening of the radiation emitted during the finite interval of time by a surface of a collapsing object. We study a simplified model of monochromatic radiations from a spherical surface which is…

General Relativity and Quantum Cosmology · Physics 2008-11-26 V. Frolov , K. Kim , H. K. Lee