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An emulator for the...
An emulator for the Lyman-α forest in beyond-ΛCDM cosmologies
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Pedersen, Christian (author)
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Font-Ribera, Andreu (author)
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- Rogers, Keir K. (author)
- Stockholms universitet,Fysikum,Oskar Klein-centrum för kosmopartikelfysik (OKC),University of Toronto, Canada
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McDonald, Patrick (author)
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- Peiris, Hiranya V. (author)
- Stockholms universitet,Fysikum,Oskar Klein-centrum för kosmopartikelfysik (OKC),University College London, United Kingdom
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Pontzen, Andrew (author)
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Slosar, Anže (author)
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(creator_code:org_t)
- 2021-05-13
- 2021
- English.
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In: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :5
- Related links:
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https://doi.org/10.1...
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https://doi.org/10.1...
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https://urn.kb.se/re...
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Abstract
Subject headings
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- Interpreting observations of the Lyman-alpha 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 Lambda CDM. 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 Sigma m(nu) = 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 Lambda CDM cosmology.
Subject headings
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Keyword
- cosmological parameters from LSS
- cosmological simulations
- Lyman alpha forest
- neutrino masses from cosmology
Publication and Content Type
- ref (subject category)
- art (subject category)
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