1306.5896 (Nathalie Palanque-Delabrouille et al.)

The one-dimensional Ly-alpha forest power spectrum from BOSS    [PDF]

Nathalie Palanque-Delabrouille, Christophe Yèche, Arnaud Borde, Jean-Marc Le Goff, Graziano Rossi, Matteo Viel, Éric Aubourg, Stephen Bailey, Julian Bautista, Michael Blomqvist, Adam Bolton, James S. Bolton, Nicolás G. Busca, Bill Carithers, Rupert A. C. Croft, Kyle S. Dawson, Timothée Delubac, Andreu Font-Ribera, Shirley Ho, David Kirkby, Khee-Gan Lee, Daniel Margala, Jordi Miralda-Escudé, Demitri Muna, Adam D. Myers, Pasquier Noterdaeme, Isabelle Pâris, Patrick Petitjean, Matthew M. Pieri, James Rich, Emmanuel Rollinde, Nicholas P. Ross, David J. Schlegel, Donald P. Schneider, Anže Slosar, David H. Weinberg

We have developed two independent methods to measure the one-dimensional power spectrum of the transmitted flux in the Lyman-$\alpha$ forest. The first method is based on a Fourier transform, and the second on a maximum likelihood estimator. The two methods are independent and have different systematic uncertainties. The determination of the noise level in the data spectra was subject to a novel treatment, because of its significant impact on the derived power spectrum. We applied the two methods to 13,821 quasar spectra from SDSS-III/BOSS DR9 selected from a larger sample of over 60,000 spectra on the basis of their high quality, large signal-to-noise ratio, and good spectral resolution. The power spectra measured using either approach are in good agreement over all twelve redshift bins from $ = 2.2$ to $ = 4.4$, and scales from 0.001 $\rm(km/s)^{-1}$ to $0.02 \rm(km/s)^{-1}$. We determine the methodological and instrumental systematic uncertainties of our measurements. We provide a preliminary cosmological interpretation of our measurements using available hydrodynamical simulations. The improvement in precision over previously published results from SDSS is a factor 2--3 for constraints on relevant cosmological parameters. For a $\Lambda$CDM model and using a constraint on $H_0$ that encompasses measurements based on the local distance ladder and on CMB anisotropies, we infer $\sigma_8 =0.83\pm0.03$ and $n_s= 0.97\pm0.02$ based on \ion{H}{i} absorption in the range $2.1View original: http://arxiv.org/abs/1306.5896