Groups of Galaxies

There are 406 groups; 149 of these contains five or more members within the survey. Geometric simulations guide our choice of the selection parameters; {delta}{rho}/{rho}=80 is the limiting density contrast and V0=350km/s is the fiducial velocity linking parameter.

The geometric simulations are particularly important for evaluating the impact of large-scale structure (e.g., the Great Wall) on group selection. The physical parameters of this large sample are coincident with our earlier results [126 groups in Ramella et al. (1989ApJ...344...57R)]: the median velocity dispersion in 192 (156; 229)km/s and the median blue log(M/L) is 2.38 (2.20; 2.52). The mass-to-light ratio (M/L) is in units of Msun/Lsun for an assumed Hubble constant, H0=100km/s/Mpc.