The Sloan Digital Sky Survey Data Release 7 galaxy angular power spectrum

Abstract

We calculate the angular power spectrum of galaxies selected from the Sloan Digital Sky Survey (SDSS) Data Release 7 by using a quadratic estimation method with Karhunen-Loéve compression. The primary data sample includes over 18 million galaxies covering more than 5700deg 2 after masking areas with bright objects, reddening greater than 0.2mag and seeing of more than 1.5arcsec. We test for systematic effects by calculating the angular power spectrum by SDSS stripe and find that these measurements are minimally affected by seeing and reddening. We calculate the angular power spectrum for ℓ≤ 200 multipoles by using 40 bandpowers for the full sample, and ℓ≤ 1000 multipoles using 50 bandpowers for individual stripes. We also calculate the angular power spectrum for this sample separated into 3mag bins with mean redshifts of z= 0.171, 0.217 and 0.261 to examine the evolution of the angular power spectrum. We determine the theoretical linear angular power spectrum by projecting the 3D power spectrum to two dimensions for a basic comparison to our observational results. By minimizing the χ 2 fit between these data and the theoretical linear angular power spectrum we measure a loosely constrained fit of with a linear bias of b= 0.94 ± 0.04. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.