The SDSS DR7 galaxy angular power spectrum: Volume limits and galaxy morphology

Abstract

We use a quadratic estimator with Karhunen-Loéve (KL)-compression to calculate the angular power spectrum of a volume-limited Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) galaxy sample out to l= 200. We also determine the angular power spectrum of selected subsamples with photometric redshifts z < 0.3 and 0.3 < z < 0.4 to examine the possible evolution of the angular power spectrum, as well as early-type and late-type galaxy subsamples to examine the relative linear bias. In addition, we calculate the angular power spectrum of the SDSS DR7 main galaxy sample in an ̃53.7 square degree area out to l = 1600 to determine the SDSS DR7 angular power spectrum to high multipoles. We perform a χ2 fit to compare the resulting angular power spectra to theoretical nonlinear angular power spectra to extract cosmological parameters and the linear bias. We find the best-fitting cosmological parameters of ωm = 0.267 ± 0.038 and ωb= 0.045 ± 0.012. We find an overall linear bias of b = 1.075 ± 0.056, an early-type bias of be = 1.727 ± 0.065 and a late-type bias of b1 = 1.256 ± 0.051. Finally, we present evidence of a selective misclassification of late-type galaxies as stars by the SDSS photometric data reduction pipeline in areas of high stellar density (e.g., at low Galactic latitudes). © 2012 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.