Pedersen, C;
Font-Ribera, A;
Rogers, KK;
McDonald, P;
Peiris, HV;
Pontzen, A;
Slosar, A;
(2021)
An emulator for the Lyman-α forest in beyond-ΛCDM cosmologies.
Journal of Cosmology and Astroparticle Physics
, 5
, Article 033. 10.1088/1475-7516/2021/05/033.
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Abstract
Interpreting observations of the Lyman-α forest flux power spectrum requires interpolation between a small number of expensive simulations. We present a Gaussian process emulator modelling the 1D flux power spectrum as a function of the amplitude and slope of the small-scale linear matter power spectrum, and the state of the intergalactic medium at the epoch of interest (2 < z < 4). This parameterisation enables the prediction of the flux power spectrum in extended cosmological models that are not explicitly included in the training set, eliminating the need to construct bespoke emulators for a number of extensions to ΛCDM. Our emulator is appropriate for cosmologies in which the linear matter power spectrum is described to percent level accuracy by just an amplitude and slope across the epoch of interest, and in the regime probed by eBOSS/DESI data. We demonstrate this for massive neutrino cosmologies, where the emulator is able to predict the flux power spectrum in a Σ m_{ν}=0.3 eV neutrino cosmology to sub-percent accuracy, without including massive neutrinos in the training simulations. Further parameters would be required to describe models with sharp features in the linear power, such as warm or light axion dark matter. This work will facilitate the combination of upcoming DESI data with observations of the cosmic microwave background, to obtain constraints on neutrino mass and other extensions to ΛCDM cosmology.
| Type: | Article |
|---|---|
| Title: | An emulator for the Lyman-α forest in beyond-ΛCDM cosmologies |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1088/1475-7516/2021/05/033 |
| Publisher version: | https://doi.org/10.1088/1475-7516/2021/05/033 |
| Language: | English |
| Additional information: | © 2021 The Author(s). Published by IOP Publishing Ltd on behalf of Sissa Medialab. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence (http://creativecommons.org/licenses/by/4.0/). |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10128592 |
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