2015/06/30 by Nathalie Palanque-Delabrouille, Christophe Yeche, Julien Baur +9 · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1088/1475-7516/2015/11/011
published as JCAP 11 (2015) 011 · 24 pages, 10 figures, change in notation for running of scalar index to make it compatible with that of Planck, article accepted for publication in JCAP
arxiv created 2019/09/04 · arxiv updated 2019/09/05
We present constraints on neutrino masses, the primordial fluctuation spectrum from inflation, and other parameters of the ΛCDM model, using the one-dimensional Lyα-forest power spectrum measured by Palanque-Delabrouille et al. (2013) from SDSS-III/BOSS, complemented by Planck 2015 cosmic microwave background (CMB) data and other cosmological probes. This paper improves on the previous analysis by Palanque-Delabrouille et al. (2015) by using a more powerful set of calibrating hydrodynamical simulations that reduces uncertainties associated with resolution and box size, by adopting a more flexible set of nuisance parameters for describing the evolution of the intergalactic medium, by including additional freedom to account for systematic uncertainties, and by using Planck 2015 constraints in place of Planck 2013. Fitting Lyα data alone leads to cosmological parameters in excellent agreement with the values derived independently from CMB data, except for a weak tension on the scalar index ns. Combining BOSS Lyα with Planck CMB constrains the sum of neutrino masses to ∑ mν< 0.12 eV (95% C.L.) including all identified systematic uncertainties, tighter than our previous limit (0.15 eV) and more robust. Adding Lyα data to CMB data reduces the uncertainties on the optical depth to reionization τ, through the correlation of τ with σ8. Similarly, correlations between cosmological parameters help in constraining the tensor-to-scalar ratio of primordial fluctuations r. The tension on ns can be accommodated by allowing for a running \mathrm dns/\mathrm dln k. Allowing running as a free parameter in the fits does not change the limit on ∑ mν. We discuss possible interpretations of these results in the context of slow-roll inflation.