THE DURHAM UKST GALAXY REDSHIFT SURVEY .1. LARGE-SCALE STRUCTURE IN THE UNIVERSE/

We present the first results from the Durham/UKST Galaxy Redshift Surv ey and consider their implications on current models of structure form ation, This b(J) less than or equal to 17 mag survey contains similar to 2500 galaxy redshifts sampled at a rate of 1 in 3 from the Edinburg h/Durham Southern Galaxy Catalogue. We find that the galaxy distributi on shows evidence of large 'cellular' features on 50-100 h(-1) Mpc sca les. This clustering has been statistically analysed using the 2-point correlation function, xi. The results show that the structures in thi s survey have power significantly in excess of the predictions of the standard cold dark matter (CDM) cosmological model on scales of 15-30 h(-1) Mpc, and therefore support the previous observational results fr om the APM survey. At smaller scales, we measure the one-dimensional p airwise galaxy velocity dispersion in the Durham/UKST survey to be 387 (-62)(+96) km s(-1). This is also inconsistent with the prediction of the standard CDM model, assuming linear biasing. Finally, at larger sc ales, the Durham/UKST survey has produced the most accurate detection yet of large-scale redshift space distortions due to dynamical infall of galaxies. We obtain a best estimate of Omega(0.6)/b = 0.55 +/- 0.12 , where Omega is the mean mass density of the Universe and b is the li near bias factor. Depending on the choice of b, this result is consist ent either with a low-density universe (b similar or equal to 1) or a critical-density universe (b similar or equal to 2).