An AI super-resolution field emulator for cosmological hydrodynamics: the Lyman-α forest

Fuente: arXiv
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Main Authors: Hafezianzadeh, Fatemeh, Zhang, Xiaowen, Ni, Yueying, Croft, Rupert A. C., DiMatteo, Tiziana, Qezlou, Mahdi, Bird, Simeon
Format: Preprint
Published: 2025
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author Hafezianzadeh, Fatemeh
Zhang, Xiaowen
Ni, Yueying
Croft, Rupert A. C.
DiMatteo, Tiziana
Qezlou, Mahdi
Bird, Simeon
author_facet Hafezianzadeh, Fatemeh
Zhang, Xiaowen
Ni, Yueying
Croft, Rupert A. C.
DiMatteo, Tiziana
Qezlou, Mahdi
Bird, Simeon
contents We extend our super-resolution and emulation framework for cosmological dark matter simulations to include hydrodynamics. We present a two-stage deep learning model to emulate high-resolution (HR-HydroSim) baryonic fields from low-resolution (LR-HydroSim) simulations at redshift $z = 3$. The method takes as inputs an LR-HydroSim and the high-resolution initial conditions (HR-HydroICs). First, the model stochastically generates high-resolution baryonic fields from the LR-HydroSim. Second, a deterministic emulator refines these fields using HR-HydroICs to reconstruct small-scale structures including displacement, velocity, internal energy, and gas/star classification. Trained on paired low- and high-resolution simulations produced with \texttt{MP-Gadget}, the model captures small-scale structures of the intergalactic medium and %Lyman-$α$ forest observables down to the 100 kpc pressure smoothing scale relevant to the Lyman-$α$ forest. The model achieves subpercent error for overdensity, temperature, velocity, and optical depth fields, a mean relative error of 1.07\% in the large-scale flux power spectrum (\(k < 3 \times 10^{-2}\ \mathrm{s/km}\)), and less than 10\% error in the flux probability distribution function. Notably, the two-stage model reduces the compute time by a factor of $\sim$450 compared to full smoothed particle hydrodynamics at the same resolution. This work demonstrates the potential of this framework as a powerful and efficient tool for generating high-resolution fields offering fast and accurate alternatives to traditional cosmological hydrodynamic simulations and enabling large-volume mock datasets for next-generation cosmological surveys.
format Preprint
id arxiv_https___arxiv_org_abs_2507_16189
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An AI super-resolution field emulator for cosmological hydrodynamics: the Lyman-α forest
Hafezianzadeh, Fatemeh
Zhang, Xiaowen
Ni, Yueying
Croft, Rupert A. C.
DiMatteo, Tiziana
Qezlou, Mahdi
Bird, Simeon
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
Computational Physics
We extend our super-resolution and emulation framework for cosmological dark matter simulations to include hydrodynamics. We present a two-stage deep learning model to emulate high-resolution (HR-HydroSim) baryonic fields from low-resolution (LR-HydroSim) simulations at redshift $z = 3$. The method takes as inputs an LR-HydroSim and the high-resolution initial conditions (HR-HydroICs). First, the model stochastically generates high-resolution baryonic fields from the LR-HydroSim. Second, a deterministic emulator refines these fields using HR-HydroICs to reconstruct small-scale structures including displacement, velocity, internal energy, and gas/star classification. Trained on paired low- and high-resolution simulations produced with \texttt{MP-Gadget}, the model captures small-scale structures of the intergalactic medium and %Lyman-$α$ forest observables down to the 100 kpc pressure smoothing scale relevant to the Lyman-$α$ forest. The model achieves subpercent error for overdensity, temperature, velocity, and optical depth fields, a mean relative error of 1.07\% in the large-scale flux power spectrum (\(k < 3 \times 10^{-2}\ \mathrm{s/km}\)), and less than 10\% error in the flux probability distribution function. Notably, the two-stage model reduces the compute time by a factor of $\sim$450 compared to full smoothed particle hydrodynamics at the same resolution. This work demonstrates the potential of this framework as a powerful and efficient tool for generating high-resolution fields offering fast and accurate alternatives to traditional cosmological hydrodynamic simulations and enabling large-volume mock datasets for next-generation cosmological surveys.
title An AI super-resolution field emulator for cosmological hydrodynamics: the Lyman-α forest
topic Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
Computational Physics
url https://arxiv.org/abs/2507.16189