Clustering of galaxies around radio quasars at 0.5 <= z <= 0.8

We have observed the galaxy environments around a sample of 21 radio-loud, steep-spectrum quasars at 0.5 less than or equal to z less than or equal to 0.82, spanning several orders of magnitude in radio luminosity. The observ ations also include background control fields used to obtain the excess num ber of galaxies in each quasar field. The galaxy excess was quantified usin g the spatial galaxy-quasar correlation amplitude, B-gq, and an Abell-type measurement, N-0.5. A few quasars are found in relatively rich clusters, bu t on average, they seem to prefer galaxy groups or clusters of approximatel y Abell class 0. We have combined our sample with literature samples extend ing down to z approximate to 0.2 and covering the same range in radio lumin osity. By using the Spearman statistic to disentangle redshift and luminosi ty dependences, we detect a weak, but significant, positive correlation bet ween the richness of the quasar environment and the radio luminosity of the quasar. However, we do not find any epoch dependence in B-gq, as has previ ously been reported for radio quasars and galaxies. We discuss the radio lu minosity-cluster richness link and possible explanations for the weak corre lation that is seen.