Cosmological Constraints from the SDSS Luminous Red Galaxies
Abstract
We measure the large-scale real-space power spectrum P(k) using luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS) and use this measurement to sharpen constraints on cosmological parameters from the Wilkinson Microwave Anisotropy Probe (WMAP). We employ a matrix-based power spectrum estimation method using Pseudo-Karhunen-Loeve eigenmodes, producing uncorrelated minimum-variance measurements in 20 k-bands of both the clustering power and its anisotropy due to redshift-space distortions, with narrow and well-behaved window functions in the range 0.01h/Mpc < k < 0.2h/Mpc. Results from the LRG and main galaxy samples are consistent, with the former providing higher signal-to-noise. Our results are robust to omitting angular and radial density fluctuations and are consistent between different parts of the sky. They provide a striking confirmation of the predicted large-scale LCDM power spectrum. Combining only SDSS LRG and WMAP data places robust constraints on many cosmological parameters that complement prior analyses of multiple data sets. The LRGs provide independent cross-checks on Om and the baryon fraction in good agreement with WMAP. Within the context of flat LCDM models, our LRG measurements complement WMAP by sharpening the constraints on the matter density, the neutrino density and the tensor amplitude by about a factor of two, giving Omega_m=0.24+-0.02 (1 sigma), sum m_nu < 0.9 eV (95%) and r<0.3 (95%). Baryon oscillations are clearly detected and provide a robust measurement of the comoving distance to the median survey redshift z=0.35 independent of curvature and dark energy properties. Within the LCDM framework, our power spectrum measurement improves the evidence for spatial flatness, sharpening the curvature constraint Omega_tot=1.05+-0.05 from WMAP alone to Omega_tot=1.003+-0.010. Assuming Omega_tot=1, the equation of state parameter is constrained to w=-0.94+-0.09, indicating the potential for more ambitious future LRG measurements to provide precision tests of the nature of dark energy. All these constraints are essentially independent of scales k>0.1h/Mpc and associated nonlinear complications, yet agree well with more aggressive published analyses where nonlinear modeling is crucial.
Cite
@article{arxiv.astro-ph/0608632,
title = {Cosmological Constraints from the SDSS Luminous Red Galaxies},
author = {M Tegmark and D Eisenstein and M Strauss and D Weinberg and M Blanton and J Frieman and M Fukugita and J Gunn and A Hamilton and G Knapp and R Nichol and J Ostriker and N Padmanabhan and W Percival and D Schlegel and D Schneider and R Scoccimarro and U Seljak and H Seo and M Swanson and A Szalay and M Vogeley and J Yoo and I Zehavi and K Abazajian and S Anderson and J Annis and N Bahcall and B Bassett and A Berlind and J Brinkmann and T Budavari and F Castander and A Connolly and I Csabai and M Doi and D Finkbeiner and B Gillespie and K Glazebrook and G Hennessy and D Hogg and Z Ivezic and B Jain and D Johnston and S Kent and D Lamb and B Lee and H Lin and J Loveday and R Lupton and J Munn and K Pan and C Park and J Peoples and J Pier and A Pope and M Richmond and C Rockosi and R Scranton and R Sheth and A Stebbins and C Stoughton and I Szapudi and D Tucker and D Vanden Berk and B Yanny and D York},
journal= {arXiv preprint arXiv:astro-ph/0608632},
year = {2008}
}
Comments
Matches accepted PRD version. SDSS data, likelihood code, Markov chains and ppt figures available at http://space.mit.edu/home/tegmark/sdss.html 36 journal pages, 25 figs. CosmoMC plugin at http://cosmologist.info/cosmomc/