| Abstract | A catalog of small groups of alaxies is generated by identifying regions of the north galactic cap (b" > 400 > 00) in which the surface number density of galaxies (m < 14) is enhanced. The determinations of both group existence and membership are accomplished by well-defined procedures and are based entirely on the distribution of galaxies in the sky. The limiting surface density enhancement of 10213 corresponds to a typical volume density enhancement of at least a few hundred; thus the groups are expected to be bound and relaxed systems. The members of each group are listed by NGC!IC number, along with their magnitudes, morphological types, and (where available) radial velocities. Similar data are given for those galaxies not assigned to groups (i.e., field galaxies). Various group properties such as angular size, total apparent magnitude, velocity dispersion, and apparent contamination by background or foreground objects are tabulated. A total of 737 galaxies are assigned to 103 separate groups, while 350 galaxies are assigned to the field. A map of the north galactic cap showing the galaxy distribution and the group boundaries is presented. This sample of small groups is well suited to statistical analyses because it is complete, well defined, and statistically homogeneous. The other papers in this series report initial statistical studies of the luminosity function of galaxies in small groups (Paper II), the mass-to-light ratios and crossing times in the groups (Paper III), and the multiplicity function or spectrum of group sizes (Paper IV). Additional observations of these groups (particularly radial velocities) would be most useful. Subject heading: galaxies: clusters of |
