The Lyα forest power spectrum from the sloan digital sky survey

Patrick McDonald, Uroš Seljak, Scott Burles, David H. Schlegel, David H. Weinberg, Renyue Cen, David Shih, Joop Schaye, Donald P. Schneider, Neta A. Bahcall, John W. Briggs, J. Brinkmann, Robert J. Brunner, Masataka Fukugita, James E. Gunn, Željko Ivezić, Stephen Kent, Robert H. Lupton, Daniel E. Vanden Berk

Research output: Contribution to journalArticlepeer-review

350 Scopus citations


We measure the power spectrum, P F(k, z), of the transmitted flux in the Lya forest using 3035 high-redshift quasar spectra from the Sloan Digital Sky Survey. This sample is almost 2 orders of magnitude larger than any previously available data set, yielding statistical errors of ∼0.6% and ∼0.005 on, respectively, the overall amplitude and logarithmic slope of P F(k, z). This unprecedented statistical power requires a correspondingly careful analysis of the data and of possible systematic contaminations in it. For this purpose we reanalyze the raw spectra to make use of information not preserved by the standard pipeline. We investigate the details of the noise in the data, resolution of the spectrograph, sky subtraction, quasar continuum, and metal absorption. We find that background sources such as metals contribute significantly to the total power and have to be subtracted properly. We also find clear evidence for Si in correlations with the Lya forest and suggest a simple model to account for this contribution to the power. Our tests indicate that any residual systematics in the analysis are unlikely to affect the inference of cosmological parameters from P F(k, z). These results should provide an essential ingredient for all future attempts to constrain modeling of structure formation, cosmological parameters, and theories for the origin of primordial fluctuations.

Original languageEnglish (US)
Pages (from-to)80-109
Number of pages30
JournalAstrophysical Journal, Supplement Series
Issue number1
StatePublished - Mar 2006

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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