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This content will become publicly available on December 1, 2025

Title: FlexRT — A fast and flexible cosmological radiative transfer code for reionization studies. Part I. Code validation
Abstract The wealth of high-quality observational data from the epoch of reionization that will become available in the next decade motivates further development of modeling techniques for their interpretation. Among the key challenges in modeling reionization are (1) its multi-scale nature, (2) the computational demands of solving the radiative transfer (RT) equation, and (3) the large size of reionization's parameter space. In this paper, we present and validate a new RT code designed to confront these challenges.FlexRT(Flexible Radiative Transfer) combines adaptive ray tracing with a highly flexible treatment of the intergalactic ionizing opacity. This gives the user control over how the intergalactic medium (IGM) is modeled, and provides a way to reduce the computational cost of aFlexRTsimulation by orders of magnitude while still accounting for small-scale IGM physics. Alternatively, the user may increase the angular and spatial resolution of the algorithm to run a more traditional reionization simulation.FlexRThas already been used in several contexts, including simulations of the Lyman-αforest of high-zquasars, the redshifted 21cm signal from reionization, as well as in higher resolution reionization simulations in smaller volumes. In this work, we motivate and describe the code, and validate it against a set of standard test problems from the Cosmological Radiative Transfer Comparison Project. We find thatFlexRTis in broad agreement with a number of existing RT codes in all of these tests. Lastly, we compareFlexRTto an existing adaptive ray tracing code to validateFlexRTin a cosmological reionization simulation.  more » « less
Award ID(s):
2045600
PAR ID:
10616024
Author(s) / Creator(s):
;
Publisher / Repository:
IOP Publishing
Date Published:
Journal Name:
Journal of Cosmology and Astroparticle Physics
Volume:
2024
Issue:
12
ISSN:
1475-7516
Page Range / eLocation ID:
025
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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