identify groups where Hickson’s approach is least effective; the two compact group surveys complement one another.

The Compact Group Catalog
=========================

The search algorithm, applied to the CfA2+SSRS2 survey, yields a catalog of 89 groups of three or more galaxies with properties similar to the HCG’s. There are 50 groups in CfAnorth, 23 groups in CfAsouth and 16 groups in the SSRS. 15 of these groups are HCG’s or subsets of HCG’s. Table \[tab:prop\] lists the locations and basic properties of these groups. The median redshift of our sample of compact groups is $z=0.014$, only half of the median HCG redshift, $z=0.030$.

Figures \[fig:rscg7\] and \[fig:rscg47\] show Digitized Sky Survey images of RSCG 7 and RSCG 47, respectively. Neither RSCG is an HCG. In each image, the inner circle is the smallest circle containing the centers of all member galaxies. It has angular radius $\theta_G = 2.94$ arcmin for RSCG 7 and $\theta_G=
2.14$ acrmin for RSCG 47. The outer circle has radius $3\theta_G$. RSCG 7, a group with $N = 3$, has galaxies in its isolation annulus. The two brightest galaxies in this annulus are in the survey, but their velocities are about 1600 km s$^{-1}$ from the group 