THE DURHAM UKST GALAXY REDSHIFT SURVEY - IV - REDSHIFT-SPACE DISTORTIONS IN THE 2-POINT CORRELATION-FUNCTION/

We have investigated the redshift-space distortions in the optically s elected Durham/UKST Galaxy Redshift Survey using the two-point galaxy correlation function perpendicular and parallel to the observer's line of sight, xi(sigma, pi). On small, non-linear scales we observe an el ongation of the constant xi (sigma, pi) contours in the line-of-sight direction. This is a result of the galaxy velocity dispersion and is t he common 'Finger of God' effect seen in redshift surveys. Our result for the one-dimensional pairwise rms velocity dispersion is [w(2)](1/2 )=416+/-36 km s(-1), which is consistent with those from recent redshi ft surveys and canonical values, but inconsistent with SCDM or LCDM mo dels. On larger, linear scales we observe a compression of the xi(sigm a, pi) contours in the line-of-sight direction. This is caused by the infall of galaxies into overdense regions, and the Durham/UKST data fa vours a value of (Ohm(0.6)/b) similar to 0.5, where Ohm is the mean ma ss density of the Universe and b is the linear bias factor that relate s the galaxy and mass distributions. Comparison with other optical est imates yields consistent results, with the conclusion that the data do not favour an unbiased critical-density universe.