Compact groups (CGs) of galaxies-relatively poor groups of galaxies in which the typical separations between members is of the order of a galaxy diameter-offer an exceptional laboratory for the study of dense galactic environments with short (<1 Gyr) dynamical timescales. We present an objectively defined catalog of CGs in 153 deg2 of the Sloan Digital Sky Survey (SDSS) Early Data Release. To identify CGs, we applied a modified version of Hickson's criteria of 1982 aimed at finding the highest-density CGs and thus reducing the number of chance alignments. Our catalog contains 175 CGs down to a limiting galaxy magnitude of r*=21. The resulting catalog has a median depth of zmed~0.13, substantially deeper than previous CG catalogs. Since the SDSS will eventually image up to one-quarter of the celestial sphere, we expect our final catalog, based on the completed SDSS, will contain on the order of 5000-10,000 CGs. This catalog will be useful for conducting studies of the general characteristics of CGs, their environments, and their component galaxies.
The Astronomical Journal
- Pub Date:
- April 2004
- 61 pages, 15 figures (Figs. 13, 14, 15 are jpegs). Atlas of compact groups (Fig. 16) is available at http://home.fnal.gov/~sallam/LeeCG/ . Accepted for publication by the Astronomical Journal