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Related papers: RAIKOU: A General Relativistic, Multi-wavelength R…

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In this Letter we consider the radial infall along the symmetry axis of an ultra-relativistic point particle into a rotating Kerr black hole. We use the Sasaki-Nakamura formalism to compute the waveform, energy spectra and total energy…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Vitor Cardoso , Jose' P. S. Lemos

We describe a code designed for hot media {(T $\ge$} a few 10$^4$ K), optically thick to Compton scattering. It computes the structure of a plane-parallel slab of gas in thermal and ionization equilibrium, illuminated on one side or on both…

Astrophysics · Physics 2009-09-25 Anne-Marie Dumont , Suzy Collin

In the vicinity of black holes, the influence of strong gravity, plasma physics, and emission processes govern the behavior of the system. Since observations such as those carried out by the EHT are not yet able to unambiguously constrain…

High Energy Astrophysical Phenomena · Physics 2023-03-22 Jan Röder , Alejandro Cruz-Osorio , Christian M. Fromm , Yosuke Mizuno , Ziri Younsi , Luciano Rezzolla

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

The inverse Compton (IC) scattering of relativistic electrons is one of the major gamma-ray production mechanisms in different environments. Often the target photons for the IC scattering are dominated by black (or grey) body radiation. In…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Dmitry Khangulyan , Felix A. Aharonian , Stanislav R. Kelner

Emission features formed through Raman scattering with atomic hydrogen provide unique and crucial information to probe the distribution and kinematics of a thick neutral region illuminated by a strong far UV emission source. We introduce a…

Solar and Stellar Astrophysics · Physics 2021-01-13 Seok-Jun Chang , Hee-Won Lee

We present recent developments on numerical algorithms for computing photon and particle trajectories in the surrounding of compact objects. Strong gravity around neutron stars or black holes causes relativistic effects on the motion of…

High Energy Astrophysical Phenomena · Physics 2020-04-08 Fabio Bacchini , Bart Ripperda , Lorenzo Sironi

The Event Horizon Telescope (EHT) has recently released high-resolution images of accretion flows onto two supermassive black holes. Our physical understanding of these images depends on accuracy and precision of numerical models of plasma…

Instrumentation and Methods for Astrophysics · Physics 2023-03-08 Monika Moscibrodzka , Aristomenis Yfantis

This paper presents OCTOPUS, a relativistic ray-tracing algorithm developed within a Fortran-based, OpenMP-accelerated framework, designed for asymptotically flat, spherically symmetric curved spacetimes. The code efficiently and accurately…

General Relativity and Quantum Cosmology · Physics 2025-10-15 Shiyang Hu , Shijie Tan , Dan Li , Lina Zhang , Chen Deng , Wenfu Cao

To facilitate the study of black hole fueling, star formation, and feedback in galaxies, we outline a method for treating the radial forces on interstellar gas due to absorption of photons by dust grains. The method gives the correct…

Astrophysics of Galaxies · Physics 2015-06-04 G. S. Novak , J. P. Ostriker , L. Ciotti

We present a comprehensive analytical study of radiative transfer using the method of moments and include the effects of non-isotropic scattering in the coherent limit. Within this unified formalism, we derive the governing equations and…

Earth and Planetary Astrophysics · Physics 2015-06-19 Kevin Heng , João M. Mendonça , Jae-Min Lee

Data derived from general relativistic magnetohydrodynamic simulations of accretion onto black holes can be used as input to a postprocessing scheme that predicts the radiated spectrum. Combining a relativistic Compton scattering radiation…

High Energy Astrophysical Phenomena · Physics 2025-04-03 Rongrong Liu , Chris Nagele , Julian H Krolik , Brooks E Kinch , Jeremy Schnittman

The advent of high-fidelity imaging of supermassive black holes calls for efficient and robust data-analysis methods. In this work, we use $\texttt{Jipole}$, a differentiable, $\texttt{ipole}$-based radiative transfer code, to enable…

High Energy Astrophysical Phenomena · Physics 2026-04-15 Pedro Naethe Motta , Mário Raia Neto , Cora Prather , Alejandro Cárdenas-Avendaño

Predicting the emerging X-ray spectra in several astrophysical objects is of great importance, in particular when the observational data are compared with theoretical models. To this aim, we have developed an algorithm solving the radiative…

High Energy Astrophysical Phenomena · Physics 2012-01-11 R. Farinelli , C. Ceccobello , P. Romano , L. Titarchuk

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 present a general formulation for ray-tracing calculations in curved space-time. The formulation takes full account of relativistic effects in the photon transport and the relative motions of the emitters and the light-of-sight absorbing…

Astrophysics · Physics 2009-11-10 Steven V. Fuerst , Kinwah Wu

In this paper we present a major update to the general relativistic magnetohydrodynamics (GRMHD) code cuHARM, which adds fully covariant treatment of radiation transport and the subsequent radiation backreaction on the dynamics of the…

High Energy Astrophysical Phenomena · Physics 2025-08-22 John Wallace , Damien Bégué , Asaf Pe'er

We present the publicly available model \textsc{reltrans} that calculates the light-crossing delays and energy shifts experienced by X-ray photons originally emitted close to the black hole when they reflect from the accretion disk and are…

High Energy Astrophysical Phenomena · Physics 2019-07-10 Adam Ingram , Guglielmo Mastroserio , Thomas Dauser , Pieter Hovenkamp , Michiel van der Klis , Javier A. García

We simulate convection near the solar surface, where the continuum optical depth is of order unity. Hence, to determine the radiative heating and cooling in the energy conservation equation, we must solve the radiative transfer equation…

Astrophysics · Physics 2007-05-23 Robert Stein , Aake Nordlund

We briefly review a fruitful approach to compute a variety of radiation signatures of General Relativity (GR) originating from accretion disks in strong gravity. A set of transfer functions can be pre-computed and then employed to…

High Energy Astrophysical Phenomena · Physics 2019-07-23 Vladimir Karas , Michal Bursa , Michal Dovciak