An End-to-End Numerical Framework for Tidal Disruption Events with AthenaK
Abstract
In a tidal disruption event (TDE), a black hole (BH) tears apart a star, whose bound debris returns over many orbits to form an accretion disk. We present a framework built on the GPU-accelerated finite-volume code \texttt{AthenaK} that follows these stages in a single simulation with self-gravity throughout. We extend \texttt{AthenaK} with a moving frame, restart remapping between domains, an adaptive-mesh multigrid Poisson solver, a tabulated hydrogen--helium equation of state including recombination, a dual-energy update for the cold supersonic debris stream, a moving BH potential with excision, and localized adaptive time stepping (LAT), which speeds up the production run more than threefold. Each component is validated separately and in combination: the gravity solver maintains an isolated Lane--Emden sphere to a density error of 2.0×10−3 over 16.3 dynamical times, and dual-energy recovery reduces the pressure error of a Mach 7.75×107 entropy wave from 15.7 to 4.0×10−12. We demonstrate the framework with a Newtonian β=1 disruption of a 1 M⊙, 1 R⊙ star by a 103 M⊙ BH. The debris has the expected energy spread, insensitive to the self-gravity update interval, splits evenly into bound and unbound material, and yields a fallback rate approaching t−5/3 at late times. At the pericenter nozzle, the thermal energy gained in the high-resolution run matches the vertical kinetic energy lost to within 6\%, whereas the fiducial run, with 4--8 times coarser cells, overheats the thinnest early stream through numerical dissipation. Their heating agrees to 10\% once the returning stream thickens. Multifrequency LTE post-processing produces synthetic images and luminosities.
Related
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BibTeX
@misc{jiang2026endtoend,
title = {{An End-to-End Numerical Framework for Tidal Disruption Events with AthenaK}},
author = {Hong-Xuan Jiang and Mengqi Yang and David A. Velasco-Romero and Fangyuan Yu and Jing-Ze Xia and Xinyu Li and Yosuke Mizuno},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.37859},
eprint = {2609.37859},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.37859},
}
RIS
TY - UNPB
TI - An End-to-End Numerical Framework for Tidal Disruption Events with AthenaK
AU - Hong-Xuan Jiang
AU - Mengqi Yang
AU - David A. Velasco-Romero
AU - Fangyuan Yu
AU - Jing-Ze Xia
AU - Xinyu Li
AU - Yosuke Mizuno
PY - 2026
DA - 2026/10/05
PB - arXiv
DO - 10.48550/arxiv.2609.37859
UR - https://arxiv.org/abs/2609.37859
AB - In a tidal disruption event (TDE), a black hole (BH) tears apart a star, whose bound debris returns over many orbits to form an accretion disk. We present a framework built on the GPU-accelerated finite-volume code \texttt{AthenaK} that follows these stages in a single simulation with self-gravity throughout. We extend \texttt{AthenaK} with a moving frame, restart remapping between domains, an adaptive-mesh multigrid Poisson solver, a tabulated hydrogen--helium equation of state including recombination, a dual-energy update for the cold supersonic debris stream, a moving BH potential with excision, and localized adaptive time stepping (LAT), which speeds up the production run more than threefold. Each component is validated separately and in combination: the gravity solver maintains an isolated Lane--Emden sphere to a density error of 2.0×10^−3 over 16.3 dynamical times, and dual-energy recovery reduces the pressure error of a Mach 7.75×10^7 entropy wave from 15.7 to 4.0×10^−12. We demonstrate the framework with a Newtonian β=1 disruption of a 1 M_⊙, 1 R_⊙ star by a 10^3 M_⊙ BH. The debris has the expected energy spread, insensitive to the self-gravity update interval, splits evenly into bound and unbound material, and yields a fallback rate approaching t^−5/3 at late times. At the pericenter nozzle, the thermal energy gained in the high-resolution run matches the vertical kinetic energy lost to within 6\%, whereas the fiducial run, with 4--8 times coarser cells, overheats the thinnest early stream through numerical dissipation. Their heating agrees to 10\% once the returning stream thickens. Multifrequency LTE post-processing produces synthetic images and luminosities.
ER -