Galaxy Groups in the Third Data Release of the Sloan Digital Sky Survey

MANUEL MERCHÁN; ARIEL ZANDIVAREZ

ASTROPHYSICAL JOURNAL

University of Chicago Press Journal Division - The American Astronomical Society

Lugar: Tucson, Arizona, USA; Año: 2005 vol. 630 p. 759 - 763

0004-637X

We present a new sample of galaxy groups identified in the Sloan Digital Sky Survey Data Release 3. Following previous works, we use the well-tested friends-of-friends algorithm developed by Huchra and Geller, which takes into account the number density variation due to the apparent magnitude limit of the galaxy catalog. To improve the identification, we implement a procedure to avoid the artificial merging of small systems in high-density regions and then apply an iterative method to recompute the group centers position. As a result, we obtain a new catalog with 10,864 galaxy groups with at least four members. The final group sample has a mean redshift of 0.1 and a median velocity dispersion of 230 km s-1.