The one-dimensional Lyα forest power spectrum from BOSS

• Published in: Astronomy and astrophysics (Berlin) Vol. 559; pp. A85 - 19
• Main Authors: Palanque-Delabrouille, Nathalie, Yèche, Christophe, Borde, Arnaud, Le Goff, Jean-Marc, Rossi, Graziano, Viel, Matteo, Aubourg, Éric, Bailey, Stephen, Bautista, Julian, Blomqvist, Michael, Bolton, Adam, Bolton, James S., Busca, Nicolás G., Carithers, Bill, A. C. Croft, Rupert, Dawson, Kyle S., Delubac, Timothée, Font-Ribera, Andreu, Ho, Shirley, Kirkby, David, Lee, Khee-Gan, Margala, Daniel, Miralda-Escudé, Jordi, Muna, Demitri, Myers, Adam D., Noterdaeme, Pasquier, Pâris, Isabelle, Petitjean, Patrick, Pieri, Matthew M., Rich, James, Rollinde, Emmanuel, Ross, Nicholas P., Schlegel, David J., Schneider, Donald P., Slosar, Anže, Weinberg, David H.
• Format: Journal Article
• Language: English
• Published: United States EDP Sciences 01.11.2013
• Subjects: Anisotropy; ASTRONOMY AND ASTROPHYSICS; Astrophysics; Bosses; Brackets; cosmological parameters; cosmology; Cosmology and Extra-Galactic Astrophysics; cosmology: observations; Forests; intergalactic medium; large-scale structure of Universe; Mathematical models; observations; Physics; Quasars; Spectra; Uncertainty; intergalactic medium; cosmology: observations; cosmological parameters; large-scale structure of Universe
• ISSN: 0004-6361; 1432-0746
• DOI: 10.1051/0004-6361/201322130

We have developed two independent methods for measuring the one-dimensional power spectrum of the transmitted flux in the Lyman-α 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. Determination of the noise level in the data spectra was subject to a new 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, high signal-to-noise ratio (S/N), and good spectral resolution. The power spectra measured using either approach are in good agreement over all twelve redshift bins from ⟨z⟩ = 2.2 to ⟨z⟩ = 4.4, and scales from 0.001 km s-1 to 0.02 km s-1. We determined the methodological andinstrumental 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 ΛCDM model and using a constraint on H0 that encompasses measurements based on the local distance ladder and on CMB anisotropies, we infer σ8 = 0.83 ± 0.03 and ns = 0.97 ± 0.02 based on H i absorption in the range 2.1 < z < 3.7.