Redshift-Space Distortions of Group and Galaxy Correlations

The two-point correlation function is computed for galaxies and groups of galaxies selected using 3-dimensional information from the Updated Zwicky Galaxy Catalog - (UZC). The redshift space distortion of the correlation function $\xi(\sigma,\pi)$ in the directions parallel and perpendicular to the line of sight, induced by pairwise group peculiar velocities is evaluated. Two methods are used to characterize the pairwise velocity field of groups and galaxies. The best fitting parameters are $\gamma=-1.89 \pm 0.17$ and $r_0=9.7 \pm 4.5$ $h^{-1}$ Mpc for groups, and $\gamma=-2.00 \pm 0.03$ and $r_0=5.29 \pm 0.21$ $h^{-1}$ Mpc for galaxies. We find $\beta_{gx}=0.51 \pm 0.15$ for galaxies, while for groups we obtain a noisy estimate $\beta < 1.5$.