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.
@article{arxiv.2207.06445,
title = {A Multi-Fidelity Emulator for the Lyman-$\alpha$ Forest Flux Power Spectrum},
author = {M. A. Fernandez and Ming-Feng Ho and Simeon Bird},
journal= {arXiv preprint arXiv:2207.06445},
year = {2022}
}