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Thermochemistry, ray-tracing radiation, and radiation-matter interactions are important processes which are computationally difficult to model in astrophysical simulations, addressed by introducing novel algorithms optimized for…

Instrumentation and Methods for Astrophysics · Physics 2026-02-03 Lile Wang

Correctly modelling the absorptive properties of dust and haze particles is of great importance for determining the abundance of solid matter within protoplanetary disks and planetary atmospheres. Rigorous analyses such as the discrete…

Earth and Planetary Astrophysics · Physics 2024-10-30 M. G. Lodge , H. R. Wakeford , Z. M. Leinhardt

We present a new chemodynamical code - Ramses-CH - for use in simulating the self-consistent evolution of chemical and hydrodynamical properties of galaxies within a fully cosmological framework. We build upon the adaptive mesh refinement…

Astrophysics of Galaxies · Physics 2015-06-04 C. Gareth Few , Stephanie Courty , Brad K. Gibson , Daisuke Kawata , Francesco Calura , Romain Teyssier

A Ramsey-type interferometer is suggested, employing a cold trapped ion and two time-delayed off-resonant femtosecond laser pulses. The laser light couples to the molecular polarization anisotropy, inducing rotational wavepacket dynamics.…

Quantum Physics · Physics 2015-02-20 J. Martin Berglund , Michael Drewsen , Christiane P. Koch

We apply a new method of eclipse mapping to the light curves of eclipsing polars. The technique aims to locate the bright emission associated with the accretion stream, using a technique that makes the fewest prior assumptions about the…

Astrophysics · Physics 2007-05-23 C. M. Bridge , Pasi Hakala , Mark Cropper , Gavin Ramsay

We present the newly-incorporated gray radiation hydrodynamics capabilities of the FLASH code based on a radiation flux-limiter aware hydrodynamics numerical implementation designed specifically for applications in astrophysical problems.…

Solar and Stellar Astrophysics · Physics 2019-08-27 Emmanouil Chatzopoulos , Klaus Weide

The Lyman-alpha reference sample (LARS) is a program with the Hubble Space Telescope (HST) that provides a sample of local universe laboratory galaxies in which to study the astrophysics of the visibility and strength of the Lyman-alpha…

We use the spectral synthesis code Cloudy to tabulate the properties of gas for an extensive range in redshift (z=0 to 9), temperature (log T [K] = 1 to 9.5), metallicity (log Z/$\mathrm{Z}_{\odot}$ = -4 to +0.5, Z=0), and density (log…

Astrophysics of Galaxies · Physics 2020-08-05 Sylvia Ploeckinger , Joop Schaye

A new code for evaluation of light absorption and scattering by interstellar dust grains is presented. The radiative transfer problem is solved using ray-tracing algorithm in a self-consistent and highly efficient way. The code demonstrates…

Astrophysics · Physics 2007-05-23 D. Semionov , V. Vansevicius

We have implemented non-ideal Magneto-Hydrodynamics (MHD) effects in the Adaptive Mesh Refinement (AMR) code RAMSES, namely ambipolar diffusion and Ohmic dissipation, as additional source terms in the ideal MHD equations. We describe in…

Solar and Stellar Astrophysics · Physics 2015-10-22 J. Masson , R. Teyssier , C. Mulet-Marquis , P. Hennebelle , G. Chabrier

Radiation controls the dynamics and energetics of many astrophysical environments. To capture the coupling between the radiation and matter, however, is often a physically complex and computationally expensive endeavour. We develop a…

Instrumentation and Methods for Astrophysics · Physics 2022-01-19 N. Moens , J. O. Sundqvist , I. El Mellah , L. Poniatowski , J. Teunissen , R. Keppens

Probing an atomic resonance without disturbing it is an ubiquitous issue in physics. This problem is critical in high-accuracy spectroscopy or for the next generation of atomic optical clocks. Ultra-high resolution frequency metrology…

We present a new numerical scheme to solve the transfer of diffuse radiation on three-dimensional mesh grids which is efficient on processors with highly parallel architecture such as recently popular GPUs and CPUs with multi- and many-core…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Satoshi Tanaka , Kohji Yoshikawa , Takashi Okamoto , Kenji Hasegawa

We propose an explicit-implicit scheme for numerically solving Special Relativistic Radiation Hydrodynamic (RRHD) equations, which ensures a conservation of total energy and momentum (matter and radiation). In our scheme, 0th and 1st moment…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Hiroyuki R. Takahashi , Ken Ohsuga , Yuichiro Sekiguchi , Tsuyoshi Inoue , Kengo Tomida

One of the major challenges in realizing antiferromagnetic and superfluid phases in optical lattices is the ability to cool fermions. We determine constraints on the entropy for observing these phases in two-dimensional Hubbard models. We…

Quantum Gases · Physics 2015-05-13 Thereza Paiva , Richard Scalettar , Mohit Randeria , Nandini Trivedi

Underwater optical imaging is severely degraded by light absorption, scattering, and color distortion, hindering visibility and accurate image analysis. This paper presents an adaptive enhancement framework integrating illumination…

Computer Vision and Pattern Recognition · Computer Science 2025-03-06 Yuezhe Tian , Kangchen Yao , Xiaoyang Yu

We present a new detailed model of the He I collisional-recombination spectrum based on the most up-to-date atomic data. The model accounts for radiative transfer effects and the influence of a non-zero optical depth in He I lines arising…

Astrophysics of Galaxies · Physics 2026-01-21 Oleg Kurichin , Alexandre Ivanchik

Ramsey spectroscopy in large, dense ensembles of ultra-cold atoms trapped in optical lattices suffers from dipole-dipole interaction induced shifts and collective superradiance limiting its precision and accuracy. We propose a novel…

Quantum Gases · Physics 2022-01-25 Christoph Hotter , Laurin Ostermann , Helmut Ritsch

We present new methodological features and physical ingredients included in the 1D radiative transfer code HELIOS, improving the hemispheric two-stream formalism. We conduct a thorough intercomparison survey with several established forward…

We develop a method of analyzing radio frequency spectral line observations to derive data on the temperature, density, velocity, and molecular abundance of the emitting gas. The method incorporates a radiative transfer code with a new…

Astrophysics · Physics 2009-11-10 Eric Keto , George B. Rybicki , Edwin A. Bergin , Rene Plume