Measuring the matter density using baryon oscillations in the SDSS

Will J. Percival, Robert C. Nichol, Daniel J. Eisenstein, David H. Weinberg, Masataka Fukugita, Adrian C. Pope, Donald P. Schneider, Alex S. Szalay, Michael S. Vogeley, Idit Zehavi, Neta A. Bahcall, Jon Brinkmann, Andrew J. Connolly, Jon Loveday, Avery Meiksin

Research output: Contribution to journalArticlepeer-review

132 Scopus citations


We measure the cosmological matter density by observing the positions of baryon acoustic oscillations in the clustering of galaxies in the Sloan Digital Sky Survey (SDSS). We jointly analyze the main galaxies and LRGs in the SDSS DR5 sample, using over half a million galaxies in total. The oscillations are detected with 99.74% confidence (3.0 σ assuming Gaussianity) compared to a smooth power spectrum. When combined with the observed scale of the peaks within the CMB, we find a best-fit value of ΩM = 0.256 -0.029+0.029 (68% confidence interval) for a flat A cosmology when marginalizing over the Hubble parameter and the baryon density. This value of the matter density is derived from the locations of the baryon oscillations in the galaxy power spectrum and in the CMB, and does not include any information from the overall shape of the power spectra. This is an extremely clean cosmological measurement, as the physics of the baryon acoustic oscillation production is well understood, and the positions of the oscillations are expected to be independent of systematics such as galaxy bias.

Original languageEnglish (US)
Pages (from-to)51-55
Number of pages5
JournalAstrophysical Journal
Issue number1 I
StatePublished - Mar 1 2007

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Cosmological parameters
  • Large-scale structure of universe


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