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Related papers: Full non-LTE spectral line formation I. Setting th…

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We study thermal radiation outside equilibrium. The situation considered consists of two bodies emitting photons at two different temperatures. We show that the system evolves to a stationary state characterized by an energy current which…

Statistical Mechanics · Physics 2017-02-01 Agustin Perez-Madrid , J. Miguel Rubi , Luciano C. Lapas

Thermodynamic characteristics of the radiation of condensed combustion products presented in the form of agglomerates of metal-oxide nanoparticles demonstrate deviations from the classical Planck's law. We propose to interpret these…

Plasma Physics · Physics 2022-03-29 G. S. Dragan , V. V. Kutarov , A. Y. Bekshaev

With the goal of producing a reliable set of model atoms and singly-ionized ions for use in building NLTE model atmospheres, we have combined measured energy levels, critically-compiled line transition probabilities, and resonance-averaged…

Astrophysics · Physics 2009-11-07 C. Allende Prieto , D. L. Lambert , I. Hubeny , T. Lanz

We present a novel ray acceleration structure for radiative transfer outside of local thermodynamic equilibrium (non-LTE), leveraging techniques from computer graphics to improve computational efficiency. By applying mipmapping (local…

Instrumentation and Methods for Astrophysics · Physics 2025-11-12 Christopher M. J. Osborne

Rapidly growing datasets from stellar spectroscopic surveys are providing unprecedented opportunities to analyse the chemical evolution history of our Galaxy. However, spectral analysis requires accurate modelling of synthetic stellar…

Solar and Stellar Astrophysics · Physics 2024-03-29 J. W. E. Mallinson , K. Lind , A. M. Amarsi , K. Youakim

The present work proposes a self-consistent reduced-order NLTE kinetic model for radiating plasmas such as are found in the outer layers of stellar atmospheres. Starting from the most up-to-date set of ab-initio and experimental data, the…

Solar and Stellar Astrophysics · Physics 2017-04-12 A. Munafo , N. Mansour , M. Panesi

We investigate the ability of both LTE and Non-LTE models to fit the near UV band absolute flux distribution and individual spectral line profiles of three standard stars for which high quality spectrophotometry and high resolution…

Astrophysics · Physics 2011-02-11 C. Ian Short , P. H. Hauschildt

A full symmetry classification is given for models of energy transport in radiant plasma when the mass density is spatially variable and the diffusivity is nonlinear. A systematic search for conservation laws also leads to some potential…

Mathematical Physics · Physics 2015-06-18 P. Broadbridge , N. M. Ivanova

Carbon abundances in late-type stars are important in a variety of astrophysical contexts. However C i lines, one of the main abundance diagnostics, are sensitive to departures from local thermodynamic equilibrium (LTE). We present a model…

Solar and Stellar Astrophysics · Physics 2019-04-24 A. M. Amarsi , P. S. Barklem , R. Collet , N. Grevesse , M. Asplund

Line scattering polarization can be strongly affected by Rayleigh scattering by neutral hydrogen and Thompson scattering by free electrons. Often a continuum depolarization results, but the Doppler redistribution produced by the continuum…

Solar and Stellar Astrophysics · Physics 2015-06-18 T. del Pino Alemán , R. Manso Sainz , J. Trujillo Bueno

The calculation of the emerging radiation from a model atmosphere requires knowledge of the emissivity and absorption coefficients, which are proportional to the atomic level population densities of the levels involved in each transition.…

Instrumentation and Methods for Astrophysics · Physics 2024-09-25 D. Arramy , J. de la Cruz Rodríguez , J. Leenaarts

Context. Three-dimensional non-local thermodynamical equilibrium (NLTE) radiative transfer calculations are a fundamental tool for a detailed spectral analysis in stellar atmospheres, but require vast amounts of computer power. This…

Solar and Stellar Astrophysics · Physics 2023-07-12 Elias R. Udnæs , Tiago M. D. Pereira

We present a new method for the numerical solution of the radiative-transfer equation (RTE) in multidimensional scenarios commonly encountered in computational astrophysics. The method is based on the direct solution of the Boltzmann…

Computational Physics · Physics 2020-10-06 L. R. Weih , A. Gabbana , D. Simeoni , L. Rezzolla , S. Succi , R. Tripiccione

We study the evolution of photoluminescence (PL) from homogeneous and inhomogeneous ensembles of a few coupled QDs. We discuss the relation between signals from a given QD ensemble under strong and weak excitation (full inversion and linear…

Mesoscale and Nanoscale Physics · Physics 2015-03-10 Wildan Abdussalam , Paweł Machnikowski

Nonlinear wave propagation in parity-time ($\mathcal{PT}$) symmetric localized potentials is investigated analytically near a phase-transition point where a pair of real eigenvalues of the potential coalesce and bifurcate into the complex…

Pattern Formation and Solitons · Physics 2016-06-29 Sean Nixon , Jianke Yang

Context. The pursuit of more realistic spectroscopic modelling and consistent abundances has led us to begin a new series of papers designed to improve current solar and stellar abundances of various atomic species. To achieve this, we have…

Solar and Stellar Astrophysics · Physics 2020-02-12 A. J. Gallagher , M. Bergemann , R. Collet , B. Plez , J. Leenaarts , M. Carlsson , S. A. Yakovleva , A. K Belyaev

First, some superluminal phenomena and experiments are introduced briefly. Next, based on the basic principles of the special relativity, the Lorentz transformation (LT) with smaller velocity and the general Lorentz transformation (GLT)…

General Physics · Physics 2010-06-11 Yi-Fang Chang

Detailed simultaneous radiative transfer-statistical equilibrium calculations have been performed for lithium in atmospheres of solar metallicity G-M dwarfs and subgiants. Model atmospheres of stars with $3500 \le \Tf \le 6000$ K, $3.0 \le…

Astrophysics · Physics 2007-05-23 Ya. V. Pavlenko , A. Magazzu

Medium resolution J-band spectroscopy of individual red supergiant stars is a promising tool to investigate the chemical composition of the young stellar population in star forming galaxies. As a continuation of recent work on iron and…

Solar and Stellar Astrophysics · Physics 2015-06-12 Maria Bergemann , Rolf-Peter Kudritzki , Matthias Wueurl , Bertrand Plez , Ben Davies , Zach Gazak

A nonlinear quantum-optical process is considered: emission of photon pairs by the reflecting end of a fiber excited by a standing laser wave. Radiation occurs due to periodic changes in the optical length of the fiber over time. This…

Quantum Physics · Physics 2019-07-11 V. Hizhnyakov
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