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Rotation is ubiquitous among massive stars. With rotation comes a deformation to the surface geometry, which in turn leads to alterations in the distribution of parameters across the surface including surface gravity, temperature and…

Solar and Stellar Astrophysics · Physics 2023-01-11 Michael Abdul-Masih

Wave propagation in multilayered media with high material contrasts poses significant numerical challenges, as large variations in wavenumbers lead to strong reflections and complex transmission of the incoming wave field. To address these…

Numerical Analysis · Mathematics 2026-02-24 Camille Carvalho , Stéphanie Chaillat , Elsie Cortes , Chrysoula Tsogka

The characterisation of the atomic and molecular hydrogen content of high-redshift galaxies is a major observational challenge that will be addressed over the coming years with a new generation of radio telescopes. We investigate this…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-13 Alan R. Duffy , Scott T. Kay , Richard A. Battye , C. M. Booth , Claudio Dalla Vecchia , Joop Schaye

Two methods are developed for solving the steady-state spherically symmetric radiative transfer equation for resonance line radiation emitted by a point source in the Intergalactic Medium. One method is based on solving the ray and moment…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Jonathan Higgins , Avery Meiksin

Observations of neutral hydrogen in spiral galaxies reveal a sharp cutoff in the radial density profile at some distance from the center. Using 22 galaxies with known HI distributions as an example, we discuss the question of whether this…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 O. V. Abramova

Radio astronomical imaging using aperture synthesis telescopes requires deconvolution of the point spread function as well as calibration of the instrumental characteristics (primary beam) and foreground (ionospheric/atmospheric) effects.…

Instrumentation and Methods for Astrophysics · Physics 2011-11-24 Juan M. Uson , William D. Cotton

We present an evaluative study of some current methods utilized in the analysis of infrared (IR) observatinons of star-forming regions. A series of self-consistent radiative transfer models are constructed, with the outputs analysed using…

Astrophysics · Physics 2007-05-23 S. D. Doty , M. L. Palotti

Spectral distortions of the cosmic microwave background (CMB) provide a unique tool for learning about the early phases of cosmic history, reaching deep into the primordial Universe. At redshifts $z<10^6$, thermalization processes become…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-04 Jens Chluba , Andrea Ravenni , Sandeep Kumar Acharya

Radiative transfer coupled with highly realistic simulations of the solar atmosphere is routinely used to infer the physical properties underlying solar observations. Due to its computational efficiency, the method of short-characteristics…

Solar and Stellar Astrophysics · Physics 2018-04-17 Courtney L. Peck , Serena Criscuoli , Mark P. Rast

Radiation from stars and AGN plays an important role in galaxy formation and evolution, and profoundly transforms the IGM, CGM & ISM. On-the-fly RT has started being incorporated in cosmological simulations, but the complex, evolving…

Astrophysics of Galaxies · Physics 2024-11-20 Bernhard Baumschlager , Sijing Shen , James W. Wadsley

Radiative transfer describes the propagation of electromagnetic radiation through an interacting medium. This process is often simulated by the use of the Monte Carlo method, which involves the probabilistic determination and tracking of…

Instrumentation and Methods for Astrophysics · Physics 2020-03-31 A. Krieger , S. Wolf

Modelling of stellar radiative intensities in various spectral pass-bands plays an important role in stellar physics. At the same time the direct calculations of the high-resolution spectrum and then integrating it over the given spectral…

Solar and Stellar Astrophysics · Physics 2021-06-30 L. S. Anusha , A. I. Shapiro , V. Witzke , M. Cernetic , S. K. Solanki , L. Gizon

Feedback effects due to massive stars and supernovae in the first objects are shown to strongly regulate both galaxy formation/evolution and the reionization process. Here we review the most important ones in some detail. We discuss how…

Astrophysics · Physics 2007-05-23 A. Ferrara , B. Ciardi , S. Marri , P. Todini

We point out that the remarkable linearity of the ultra-steep radio spectra of high redshift radio galaxies reflects a previously reported general trend for powerful radio galaxies, according to which the spectral curvature is lesser for…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Gopal-Krishna , Mukul Mhaskey , A. Mangalam

Understanding the epochs of cosmic dawn and reionisation requires us to leverage multi-wavelength and multi-tracer observations, with each dataset providing a complimentary piece of the puzzle. To interpret such data, we update the public…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-24 James E. Davies , Andrei Mesinger , Steven Murray

Line ratios in "fir" triplets of helium-like ions have proven to be a powerful diagnostic of conditions in X-ray emitting gas surrounding massive stars. Recent observations indicate that these ratios can be variable with time. The possible…

Solar and Stellar Astrophysics · Physics 2015-06-04 K. T. Hole , R. Ignace

We consider the degree to which "21 cm tomography" of the high-redshift Universe can distinguish different ionization histories. Using a new analytic model for the size distribution of HII regions that associates these ionized bubbles with…

Astrophysics · Physics 2009-09-29 Steven Furlanetto , Matias Zaldarriaga , Lars Hernquist

We present a suite of 3D multi-physics MHD simulations following star formation in isolated turbulent molecular gas disks ranging from 5 to 500 parsecs in radius. These simulations are designed to survey the range of surface densities…

This article presents a set of spectro-goniometric measurements of different water ice samples and the comparison with an approximated radiative transfer model. The experiments were done using the spectro-radiogoniometer described in…

We construct a simple but self-consistent analytic ionization model for rapid exploration of 21cm power spectrum observables in redshift space. It is fully described by the average ionization fraction $x_e(z)$ and HII patch size $R(z)$ and…

Astrophysics · Physics 2009-11-13 Xiaomin Wang , Wayne Hu