Loose Groups of Galaxies in the Las Campanas Redshift Survey

A " friends-of-friends " percolation algorithm has been used to extract a catalogue of δn/n = 80 density enhancements (groups) from the six slices of the Las Campanas Redshift Survey (LCRS). The full catalogue contains 1495 groups and includes 35% of the LCRS galaxy sample. A clean sample of 394 groups has been derived by culling groups from the full sample which either are too close to a slice edge, have a crossing time greater than a Hubble time, have a corrected velocity dispersion of zero, or contain a 55-arcsec " orphan " (a galaxy with a mock redshift which was excluded from the original LCRS redshift catalogue due to its proximity to another galaxy — i.e., within 55 arcsec). Median properties derived from the clean sample include: line-of-sight velocity dispersion σ los = 164 km s −1 , crossing time t cr = 0.10 H