Engineering Papers⌕ Search
Home/Archive/DOE OSTI

DOE OSTI · 2568716

Mahakala: A Python-based Modular Ray-tracing and Radiative Transfer Algorithm for Curved Spacetimes

Sharma, Aniket [Indian Institute of Science Education and Research Mohali, Punjab (India)] (ORCID:0009000503983748)·Medeiros, Lia [Univ. of Wisconsin, Milwaukee, WI (United States); Princeton Univ., NJ (United States); Institute for Advanced Study, Princeton, NJ (United States)] (ORCID:0000000323426728)·Wong, George N. [Institute for Advanced Study, Princeton, NJ (United States); Princeton Univ., NJ (United States)] (ORCID:0000000169522147)·Chan, Chi-kwan [Univ. of Arizona, Tucson, AZ (United States); Univ. of Arizona, Tucson, AZ (United States). Steward Observatory] (ORCID:0000000163376126)·Halevi, Goni [Illinois Institute of Technology, Chicago, IL (United States); Northwestern Univ., Evanston, IL (United States). Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA)] (ORCID:000000027232101X)·Mullen, Patrick D. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000321314634)·Stone, James M. [Institute for Advanced Study, Princeton, NJ (United States)] (ORCID:0000000156031832)
View original source ↗Read source document ↗Export metadata ↓

Abstract

We introduce Mahakala, a Python-based, modular, radiative ray-tracing code for curved spacetimes. We employ Google's JAX framework for accelerated automatic differentiation, which can efficiently compute Christoffel symbols directly from the metric, allowing the user to easily and quickly simulate photon trajectories through non-Kerr spacetimes. JAX also enables Mahakala to run in parallel on both CPUs and GPUs. Mahakala natively uses the Cartesian Kerr–Schild coordinate system, which avoids numerical issues caused by the pole in spherical coordinate systems. We demonstrate Mahakala's capabilities by simulating 1.3 mm wavelength images (the wavelength of Event Horizon Telescope observations) of general relativistic magnetohydrodynamic simulations of low-accretion rate supermassive black holes. The modular nature of Mahakala allows us to quantitatively explore how different regions of the flow influence different image features. We show that most of the emission seen in 1.3 mm images originates close to the black hole and peaks near the photon orbit. We also quantify the relative contribution of the disk, forward jet, and counterjet to 1.3 mm images.

Explore related subjects

79 ASTRONOMY AND ASTROPHYSICSastronomical simulationsastrophysical black holesblack holescomputational methodsradiative transferradiative transfer simulationssupermassive black holes

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Sharma, Aniket [Indian Institute of Science Education and Research Mohali, Punjab (India)] (ORCID:0009000503983748), Medeiros, Lia [Univ. of Wisconsin, Milwaukee, WI (United States); Princeton Univ., NJ (United States); Institute for Advanced Study, Princeton, NJ (United States)] (ORCID:0000000323426728), Wong, George N. [Institute for Advanced Study, Princeton, NJ (United States); Princeton Univ., NJ (United States)] (ORCID:0000000169522147), Chan, Chi-kwan [Univ. of Arizona, Tucson, AZ (United States); Univ. of Arizona, Tucson, AZ (United States). Steward Observatory] (ORCID:0000000163376126), Halevi, Goni [Illinois Institute of Technology, Chicago, IL (United States); Northwestern Univ., Evanston, IL (United States). Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA)] (ORCID:000000027232101X), Mullen, Patrick D. [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000321314634), Stone, James M. [Institute for Advanced Study, Princeton, NJ (United States)] (ORCID:0000000156031832). 2025-05-13. Mahakala: A Python-based Modular Ray-tracing and Radiative Transfer Algorithm for Curved Spacetimes. https://doi.org/10.3847/1538-4357%2Fadc104

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related reports

DOE OSTI2026

Dust Survival in Galactic Winds

This repository contains three-dimensional volumetric data from an Eulerian hydrodynamical simulation (conducted on a uniform Cartesian grid) generated by the Cholla hydrodynamics code. The datasets contain snapshots (full-grid, projections, and slices) in the HDF5 format of a multi-phase medium in which a hot, diffuse, dust-free background wind accelerates a cool, dense cloud of gas and dust. This scenario is intended to represent a supernova-driven galactic outflow, in which hot supernova winds are thought to accelerate cool interstellar medium material out of the galactic disk into the surrounding circumgalactic medium. There are three separate datasets for simulations corresponding to three cloud evolutionary scenarios: long-term cloud survival (surv), marginal cloud survival (disr), and cloud destruction (dest). Projection and slice images of the simulations are also included in this repository.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Unraveling TeV halos with the Cherenkov Telescope Array

Pulsars are observed to emit bright and spatially extended gamma-ray emission at multi-TeV energies. These so-called "TeV halos" are now understood to be a nearly universal feature of middle-aged pulsars. However, many of the key physical processes that govern these systems, particularly those affecting particle diffusion, remain poorly constrained. We aim to evaluate the ability of the Cherenkov Telescope Array (CTA) to probe the physical properties of TeV halos, with a focus on the nearby and well-studied case of the Geminga pulsar. We simulate gamma-ray emission from various TeV halo models, incorporating different assumptions for the injected electron spectrum, spin-down evolution, and energy-dependent diffusion. These models are then used to forecast CTA's sensitivity to spectral and spatial differences, based on realistic mock observations and instrument response simulations. We find that CTA will be able to distinguish between a wide range of TeV halo models that are currently consistent with existing data. In particular, CTA observations can constrain the normalization, energy dependence, and spatial extent of the diffusion coefficient surrounding Geminga, as well as the spectral shape of the injected electron population.

79 ASTRONOMY AND ASTROPHYSICS↗