Cosmological parameters from recent cosmological datasets including Lyman-α forest data

Abstract

We combine the high resolution spectra with cosmic microwave background (CMB) including 3-year WMAP, and supernovae (SN) and galaxy clustering constraints with the Ly-α forest power spectrum from the Sloan Digital Sky Survey (SDSS) to derive new constraints on cosmological parameters. The existing Ly-α power spectrum analysis is supplemented by constraints on the mean flux decrement which were derived by a principle component analysis of quasar continua. This improves the Ly-α constraints on the linear power. We find a mild conflict between the WMAP3 and Ly-α power spectrum amplitudes at the ∼2 σ level, which is partially alleviated by the inclusion of other observations: we find σ 8 = 0.85 ± 0.02 compared to σ 8 = 0.80 ± 0.03 without Ly-α. For the slope we find n s = 0.965 ± 0.012. No evidence for the running of the spectral index is found in the combined analysis, d n/d ln k = −(1.5 ± 1.2) × 10 −2, which is in agreement with inflation.