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

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-alpha forest power spectrum from the Sloan Digital Sky Survey (SDSS) to derive new constraints on cosmological parameters. The existing Ly-alpha 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-alpha constraints on the linear power. We find a mild conflict between the WMAP3 and Ly-alpha power spectrum amplitudes at the similar to 2 sigma level, which is partially alleviated by the inclusion of other observations: we find sigma(8) = 0.85 +/- 0.02 compared to sigma(8) = 0.80 +/- 0.03 without Ly-alpha. 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, dn/dInk = -(1.5 +/- 1.2) x 10(-2), which is in agreement with inflation. (c) 2006 Elsevier B.V. All rights reserved.