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Open Access Publications from the University of California

The one-dimensional Lyα forest power spectrum from BOSS

  • Author(s): Palanque-Delabrouille, N
  • Yèche, C
  • Borde, A
  • Le Goff, JM
  • Rossi, G
  • Viel, M
  • Aubourg, E
  • Bailey, S
  • Bautista, J
  • Blomqvist, M
  • Bolton, A
  • Bolton, JS
  • Busca, NG
  • Carithers, B
  • Croft, RAC
  • Dawson, KS
  • Delubac, T
  • Font-Ribera, A
  • Ho, S
  • Kirkby, D
  • Lee, KG
  • Margala, D
  • Miralda-Escudé, J
  • Muna, D
  • Myers, AD
  • Noterdaeme, P
  • Pâris, I
  • Petitjean, P
  • Pieri, MM
  • Rich, J
  • Rollinde, E
  • Ross, NP
  • Schlegel, DJ
  • Schneider, DP
  • Slosar, A
  • Weinberg, DH
  • et al.

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 Hi absorption in the range 2.1 < z < 3.7. © ESO, 2013.

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