The one-dimensional Lyα forest power spectrum from BOSS
Abstract
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.
The measured values of the power spectrum and correlation matrices for all scales and all redshifts (full Tables 4 and 5) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A85- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 2013
- DOI:
- 10.1051/0004-6361/201322130
- arXiv:
- arXiv:1306.5896
- Bibcode:
- 2013A&A...559A..85P
- Keywords:
-
- cosmology: observations;
- large-scale structure of Universe;
- intergalactic medium;
- cosmological parameters;
- Astrophysics - Cosmology and Extragalactic Astrophysics
- E-Print:
- 21 pages, 26 figures, tables available online at http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A85