Higher Order Moments of the Angular Distribution of Galaxies from Early Sloan Digital Sky Survey Data

Abstract

We present initial results for counts in cell statistics of the angular distribution of galaxies in early data from the Sloan Digital Sky Survey (SDSS). We analyze a rectangular stripe 2°.5 wide, covering approximately 160 deg2, containing over 106 galaxies in the apparent magnitude range 18 < r′ < 22, with areas of bad seeing, contamination from bright stars, ghosts, and high galactic extinction masked out. This survey region, which forms part of the SDSS early data release, is the same as that for which two-point angular clustering statistics have recently been computed. The third and fourth moments of the cell counts, s 3 (skewness) and s4 (kurtosis), constitute the most accurate measurements to date of these quantities (for r′ < 21) over angular scales 0°.015-0°.3. They display the approximate hierarchical scaling expected from nonlinear structure formation models and are in reasonable agreement with the predictions of Λ-dominated cold dark matter models with galaxy biasing that suppresses higher order correlations at small scales. The results are, in general, consistent with previous measurements in the APM, EDSGC, and Deeprange surveys. These results suggest that the SDSS imaging data are free of systematics to a high degree and will therefore enable determination of the skewness and kurtosis to 1% and less then 10%, as predicted earlier.