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In preparation of a study of the HeII/HI ratio towards the bright QSO HS1700+6416, we predict the metal line content of the far-UV spectral range by modelling 18 metal absorption line systems with redshifts 0.2<z<2.6 identified in the…

Astrophysics · Physics 2009-11-11 C. Fechner , D. Reimers , A. Songaila , R. A. Simcoe , M. Rauch , W. L. W. Sargent

We model the correlated X-ray - UV observations of NGC 7469, for which well sampled data in both these bands have been obtained recently in a multiwavelength monitoring campaign. To this end we derive the transfer function in wavelength \ls…

Astrophysics · Physics 2009-10-31 Andrew J. Berkley , Demosthenes Kazanas , Jonathan Ozik

The solar chromosphere is a region where radiation plays a critical role in energy transfer and interacts strongly with the plasma. In this layer, strong spectral lines, such as the Lyman lines, contribute significantly to radiative energy…

Solar and Stellar Astrophysics · Physics 2026-02-10 W. Ruan , D. Przybylski , R. Cameron , S. K. Solanki

Our recent re-analysis of the solar photospheric spectra with non-local thermodynamic equilibrium (non-LTE) models resulted in higher metal abundances compared to previous works. When applying the new chemical abundances to Standard Solar…

Solar and Stellar Astrophysics · Physics 2022-09-07 Manuel A. Bautista , Maria Bergemann , Helena Carvajal Gallego , Sébastien Gamrath , Patrick Palmeri , Pascal Quinet

According to a recent investigation, an estimated 33-50% of the world's coral reefs have undergone degradation, believed to be as a result of climate change. A strong driver of climate change and the subsequent environmental impact are…

Machine Learning · Computer Science 2019-06-11 Shubhankar Deshpande , Brian D. Bue , David R. Thompson , Vijay Natraj , Mario Parente

Radiative transfer models explain and predict interaction between solar radiation and the different elements present in the atmosphere, which are responsible for energy attenuation. In Colombia there have been neither measurements nor…

Atmospheric and Oceanic Physics · Physics 2012-07-31 Camilo Delgado-Correal , Jorge Hernández , Gabriel Castaño

We report a data-parsimonious machine learning model for short-term forecasting of solar irradiance. The model inputs include sky camera images that are reduced to scalar features to meet data transmission constraints. The output irradiance…

Machine Learning · Computer Science 2025-03-25 Joshua Edward Hammond , Ricardo A. Lara Orozco , Michael Baldea , Brian A. Korgel

A formal derivation is presented of the energy transfer rate between radiation and matter due to the scattering of an isotropic distribution of resonant photons. The derivation is developed in the context of the two-level atom in the…

Astrophysics · Physics 2010-04-29 Avery Meiksin

Neutral nickel (Ni I) is abundant in the solar atmosphere and is one of the important elements that contribute to the emission and absorption of radiation in the spectral range between 1900 and 3900 A. Previously, the Solar Radiation…

Solar and Stellar Astrophysics · Physics 2015-06-15 Mariela C. Vieytes , Juan M. Fontenla

We describe a general radiative equilibrium and temperature correction procedure for use in Monte Carlo radiation transfer codes with sources of temperature-independent opacity, such as astrophysical dust. The technique utilizes the fact…

Astrophysics · Physics 2010-04-08 J. E. Bjorkman , Kenneth Wood

In this paper the practical approach to evaluate the incoming solar radiation on buildings based on atmospheric composition and cloud cover is presented. The effects of absorption and scattering due to atmospheric composition is taken into…

Geophysics · Physics 2015-06-22 Jochen E. Wagner , Marcello Petitta

Analytical and numerical solutions are obtained for the equation of radiative transfer in ultra-relativistic opaque jets. The solution describes the initial trapping of radiation, its adiabatic cooling, and the transition to transparency.…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Andrei M. Beloborodov

We investigate and evaluate the contribution of the ultraviolet radiation spectrum on the temperature and efficiency of commercial crystalline silicon-based photovoltaics (PVs) that operate outdoors. The investigation is performed by…

This paper deals with an analytical modeling of heat transfers simulating a new radiation calorimeter operating in a temperature range from -50 {\deg}C to 150 {\deg}C. The aim of this modeling is the evaluation of the feasibility and…

Instrumentation and Detectors · Physics 2016-01-11 Elysée Obame Ndong , Olivier Gallot-Lavallée , Frédéric Aitken

Global and regional climate model projections are useful for gauging future patterns of climate variables, including solar radiation, but data from these models is often too coarse to assess local impacts. Within the context of solar…

Applications · Statistics 2024-05-21 Maggie Bailey , Doug Nychka , Manajit Sengupta , Jaemo Yang , Soutir Bandyopadhyay

During the epoch of reionization the 21cm signal is sensitive to the scattering rate of the ultraviolet photons, redshifting across the Lyman_alpha resonance. Here we calculate the photon scattering rate profile for a single ultraviolet…

Astrophysics · Physics 2009-11-13 Leonid Chuzhoy , Zheng Zheng

Observations and magnetohydrodynamic simulations of solar and stellar atmospheres reveal an intermittent behavior or steep gradients in physical parameters, such as magnetic field, temperature, and bulk velocities. The numerical solution of…

Solar and Stellar Astrophysics · Physics 2019-03-22 Gioele Janett

Spectra of the \ze~$=4.12$ quasar Q$0000-2619$ have been obtained in the range $\lambda\lambda = 4880-8115$ \AA~with a resolution of 13 \kms~and signal--to--noise ratio of $s/n=15-60$ per resolution element. The mode of the distribution of…

Astrophysics · Physics 2008-02-03 S. Savaglio , S. Cristiani , S. D'Odorico , A. Fontana , E. Giallongo , P. Molaro

The aim of this research is to show that the processes of absorption charge-exchange and photo-association in $A+B^{+}$ collisions together with the processes of $AB^{+}$ photo-dissociation in the case of strongly non-symmetric ion-atom…

Solar and Stellar Astrophysics · Physics 2013-02-26 A. A. Mihajlov , Lj. M. Ignjatovic , V. A. Sreckovic , M. S. Dimitrijevic , A. Metropoulos

We report on the results of the Sun in Time multi-wavelength program (X-rays to the UV) of solar analogs with ages covering ~0.1-7 Gyr. The chief science goals are to study the solar magnetic dynamo and to determine the radiative and…

Astrophysics · Physics 2009-11-10 I. Ribas , E. F. Guinan , M. Guedel , M. Audard