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arXiv · 2207.06445

A Multi-Fidelity Emulator for the Lyman-$α$ Forest Flux Power Spectrum

M. A. Fernandez·Ming-Feng Ho·Simeon Bird
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Abstract

In this work we extend our recently developed multi-fidelity emulation technique to the simulated Lyman-$α$ forest flux power spectrum. Multi-fidelity emulation allows interpolation of simulation outputs between cosmological parameters using many cheap low-fidelity simulations and a few expensive high-fidelity simulations. Using a test suite of small box (30 Mpc/h) simulations, we show that multi-fidelity emulation is able to reproduce the Lyman-$α$ forest flux power spectrum well, achieving an average accuracy when compared to a test suite of $0.8\%$. We further show that it has a substantially increased accuracy over single-fidelity emulators, constructed using either the high or low-fidelity simulations only. In particular, it allows the extension of an existing simulation suite to smaller scales and higher redshifts.

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M. A. Fernandez, Ming-Feng Ho, Simeon Bird. 2022-10-24. A Multi-Fidelity Emulator for the Lyman-$α$ Forest Flux Power Spectrum. https://doi.org/10.1093/mnras%2Fstac2435

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