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The one-dimensional Ly-alpha forest power spectrum from BOSS

Abstract : 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 $2.1
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Submitted on : Tuesday, November 12, 2013 - 4:33:26 PM
Last modification on : Saturday, September 19, 2020 - 4:50:37 AM

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Nathalie Palanque-Delabrouille, Christophe Yèche, Arnaud Borde, Jean-Marc Le Goff, Graziano Rossi, et al.. The one-dimensional Ly-alpha forest power spectrum from BOSS. Astronomy and Astrophysics - A&A, EDP Sciences, 2013, 559, pp.A85. ⟨10.1051/0004-6361/201322130⟩. ⟨in2p3-00903654⟩



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