Galaxy clustering in the Sloan Digital Sky Survey (SDSS) : A first comparison with the APM Galaxy Catalogue

E. Gaztanaga

Published 2001-06-21, updated 2001-10-09Version 5

We compare the large scale galaxy clustering in the new SDSS early data release (EDR) with the clustering in the APM Galaxy Survey. We cut out pixel maps (identical in size and shape) from the SDSS and APM data to allow a direct comparison of the clustering. Here we concentrate our analysis on an equatorial SDSS strip in the South Galactic Cap (EDR/SGC) with 166 deg^2, 2.5 wide and 65 degrees long. Only galaxies with Petrosian magnitudes 16.8 <g'<19.8 are included to match the surface density of the 17< b_J<20 APM pixel maps (median depth of 400 Mpc/h). Both the amplitude and shape of the angular 2-point function and variance turn out to be in very good agreement with the APM on scales smaller than 2 degrees (ie 15 Mpc/h). The 3-point function and skewness are also in excellent agreement within a 90% confidence level. On one hand these results illustrate that the EDR data and SDSS software pipelines, work well and are suitable to do analysis of large scale clustering. On the other hand it confirms that large scale clustering analysis is becoming "repeatable" and therefore that our conclusions for structure formation models seem to stand on solid scientific grounds.