http://arxiv.org/abs/2011.15127
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. 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. This work will facilitate the combination of upcoming data from the Dark Energy Spectroscopic Instrument with observations of the cosmic microwave background, to obtain constraints on neutrino mass and other extensions to $\Lambda$CDM cosmology.
C. Pedersen, A. Font-Ribera, K. Rogers, et. al.
Tue, 1 Dec 20
26/108
Comments: 26 pages, 11 figures
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