The two-point correlation function and morphological segregation in the Optical Redshift Survey

We study the clustering of galaxies in real and redshift space using theOptical Redshift Survey (ORS). We estimate the two point correlation functionin redshift space, $\xi(s)$, for several subsamples of ORS, spanning nearly afactor of 30 in volume and detect significant variations in $\xi(s)$ among thesubsamples covering small volumes. For volumes \gtsima $(75 h^{-1} {\rmMpc})^{3}$ the ORS subsamples present very similar clustering patterns.Powerlaw fits to $\xi(s)$ give best-fit values in the range $1.5 \leq\gamma_{s} \leq 1.7 $ and $6.5 \leq s_{0} \leq 8.8 h^{-1}$ Mpc for severalsamples extending to redshifts of 8000 km s$^{-1}$. We find that $\xi(s)$ islarger for the magnitude-limited sample than for diameter-limited one within aradius of 4000 km s$^{-1}$. We interpret this as an indirect result ofmorphological segregation coupled with differences in morphological mix. Wesplit ORS into morphological subsamples and confirm the existence ofmorphological segregation of galaxies out to scales of $s \sim 10 h^{-1}$ Mpc.Our results indicate that the relative bias factor between early type galaxiesand late-types may be weakly dependent on scale. If real, this would suggestnon-linear biasing. We also compute correlations as a function of radial andprojected separations, $\xi(r_p, \pi)$ and derive the real space correlationfunction, $\xi(r)$. The results obtained in real space confirm those foundusing $\xi(s)$.Comment: 12 pages, 13 figures. Uses mn.sty. Accepted for publication in Monthly Notice