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Atmospheric refraction modifies the apparent position of objects in the sky. We computed the lateral translation that is to be considered for short-range applications, such as wavefront sensing and meteor trajectories. We aim to calculate…

Instrumentation and Methods for Astrophysics · Physics 2022-03-08 Hanae Labriji , Olivier Herscovici-Schiller , Frédéric Cassaing

In accelerating and supersonic media, the interaction of photons with spectral lines can be of ultimate importance. However, fully accounting for such line forces currently can only be done by specialised codes in 1-D steady-state flows.…

Solar and Stellar Astrophysics · Physics 2022-11-16 L. G. Poniatowski , N. D. Kee , J. O. Sundqvist , F. A. Driessen , N. Moens , S. P. Owocki , K. G. Gayley , L. Decin , A. de Koter , H. Sana

We present a new method to retrieve molecular abundances and temperature profiles from exoplanet atmosphere photometry and spectroscopy. We run millions of 1D atmosphere models in order to cover the large range of allowed parameter space,…

Earth and Planetary Astrophysics · Physics 2014-11-20 N. Madhusudhan , S. Seager

Several variants of Neural Radiance Fields (NeRFs) have significantly improved the accuracy of synthesized images and surface reconstruction of 3D scenes/objects. In all of these methods, a key characteristic is that none can train the…

Computer Vision and Pattern Recognition · Computer Science 2025-06-11 Gonçalo Dias Pais , Valter Piedade , Moitreya Chatterjee , Marcus Greiff , Pedro Miraldo

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

We generalize the semi-analytical line transfer (SALT) model recently introduced by Scarlata \& Panagia (2015) for modeling galactic outflows, to account for bi-conical geometries of various opening angles and orientations with respect to…

Astrophysics of Galaxies · Physics 2018-07-04 Cody Carr , Claudia Scarlata , Nino Panagia , Alaina Henry

The polarization state of electromagnetic radiation scattered by atmospheric particles such as aerosols, cloud droplets, or ice crystals contains much more information about the optical and microphysical properties than the total intensity…

Earth and Planetary Astrophysics · Physics 2019-01-08 C. Emde , V. Barlakas , C. Cornet , F. Evans , S. Korkin , Y. Ota , L. C. -Labonnote , A. Lyapustin , A. Macke , B. Mayer , M. Wendisch

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

Molecules with hyperfine splitting of their rotational line spectra are useful probes of optical depth, via the relative line strengths of their hyperfine components.The hyperfine splitting is particularly advantageous in interpreting the…

Astrophysics of Galaxies · Physics 2016-04-27 A. M. Mullins , R. M. Loughnane , M. P. Redman , B. Wiles , N. Guegan , J. Barrett , E. R. Keto

We present a computational approach for solving reaction-diffusion equations on evolving surfaces which have been obtained from cell image data. It is based on finite element spaces defined on surface triangulations extracted from time…

Numerical Analysis · Mathematics 2016-06-17 Till Bretschneider , Cheng-Jin Du , Charles M. Elliott , Thomas Ranner , Bjorn Stinner

We present new methods for radiative transfer on hierarchial grids. We develop a new method for calculating the scattered flux that employs the grid structure to speed up the computation. We describe a novel subiteration algorithm that can…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 T. Lunttila , M. Juvela

The recent discovery and characterization of the diversity of the atmospheres of exoplanets and brown dwarfs calls for the development of fast and accurate analytical models. We quantify the accuracy of the analytical solution derived in…

Earth and Planetary Astrophysics · Physics 2015-01-21 Vivien Parmentier , Tristan Guillot , Jonathan J. Fortney , Mark S. Marley

Emission profiles of the resonantly scattered OII~83.4~nm triplet can in principle be used to estimate \(\mathrm{O}^+\) density profiles in the F2 region of the ionosphere. Given the emission source profile, solution of this inverse problem…

Space Physics · Physics 2016-11-08 George Geddes , Ewan Douglas , Susanna C. Finn , Timothy Cook , Supriya Chakrabarti

We investigate the ellipticity of the point-spread function (PSF) produced by imaging an unresolved source with a telescope, subject to the effects of atmospheric turbulence. It is important to quantify these effects in order to understand…

Astrophysics · Physics 2011-02-11 W. H. de Vries , S. S. Olivier , S. J. Asztalos , L. J. Rosenberg , K. L. Baker

Light emitters or scatterers embedded in stratified media may couple energy to both free space modes and guided modes of the stratified structure. For a comprehensive analysis, it is important to evaluate the angular intensity distribution…

Optics · Physics 2016-05-16 Jianji Yang , Jean-Paul Hugonin , Philippe Lalanne

We developed a three-dimensional radiative transfer code for an ultra-relativistic background flow-field by using the Monte Carlo (MC) method in the context of gamma-ray burst (GRB) emission. For obtaining reliable simulation results in the…

High Energy Astrophysical Phenomena · Physics 2017-09-13 Ayako Ishii , Naofumi Ohnishi , Hiroki Nagakura , Hirotaka Ito , Shoichi Yamada

In the present work, we investigate the potential of fractional derivatives to model atmospheric dispersion of pollutants. We propose simple fractional differential equation models for the steady state spatial distribution of concentration…

Atmospheric and Oceanic Physics · Physics 2017-02-22 A. G. O. Goulart , M. J. Lazo , J. M. S. Suarez , D. M. Moreira

In this paper, we propose a model order reduction based adaptive parareal method for time-dependent partial differential equations. By using the data obtained by the fine propagator in each iteration of the plain parareal method together…

Numerical Analysis · Mathematics 2026-01-19 Xiaoying Dai , Miao Hu , Shuwei Shen

Flourescent iron line profiles currently provide the best diagnostic for active galactic nuclei (AGN) engine geometries. Here we construct a method for calculating the relativistic iron line profile from an arbitrarily warped accretion…

Astrophysics · Physics 2011-05-10 Sean A. Hartnoll , Eric G. Blackman

The photoionization-driven evaporation of planetary atmospheres has emerged as a potentially fundamental process for planets on short period orbits. While 1-D studies have proven the effectiveness of stellar fluxes at altering the…

Earth and Planetary Astrophysics · Physics 2018-12-19 Alex Debrecht , Jonathan Carroll-Nellenback , Adam Frank , John McCann , Ruth Murray-Clay , Eric G. Blackman