Cosmic Homogeneity Demonstrated with Luminous Red Galaxies
Abstract
We test the homogeneity of the universe at z~0.3 with the luminous red galaxy (LRG) spectroscopic sample of the Sloan Digital Sky Survey. First, the mean number N(R) of LRGs within completely surveyed LRGcentered spheres of comoving radius R is shown to be proportional to R^{3} at radii greater than R~70h^{1}Mpc. The test has the virtue that it does not rely on the assumption that the LRG sample has a finite mean density; its results show, however, that there is such a mean density. Second, the survey sky area is divided into 10 disjoint solid angular regions, and the fractional rms density variations of the LRG sample in the redshift range 0.2<z<0.35 among these (~2×10^{7}h^{3}Mpc^{3}) regions is found to be 7% of the mean density. This variance is consistent with typical biased ΛCDM models and puts very strong constraints on the quality of SDSS photometric calibration.
 Publication:

The Astrophysical Journal
 Pub Date:
 May 2005
 DOI:
 10.1086/429084
 arXiv:
 arXiv:astroph/0411197
 Bibcode:
 2005ApJ...624...54H
 Keywords:

 Cosmology: Cosmological Parameters;
 Cosmology: Observations;
 Galaxies: Statistics;
 Cosmology: LargeScale Structure of Universe;
 Methods: Statistical;
 Surveys;
 Astrophysics
 EPrint:
 submitted to ApJ