THE CLUSTERING OF K-SIMILAR-TO-20 GALAXIES IN 17 RADIO GALAXY FIELDS

We investigate the angular correlation function, omega (theta), of the galaxies detected in the 2.1-mu m K' band in 17 fields (101.5 arcmin( 2) in total), each containing a z similar to 1.1 radio galaxy. There i s a significant detection of galaxy clustering at a limit of K similar to 20, with a omega (theta) amplitude similar to that estimated by Ca rlberg et al. at K= 21.5. The omega (theta) amplitudes of these K-limi ted samples are higher than expected from the faint galaxy clustering in the blue and red passbands, but consistent with a pure luminosity e volution model if clustering is stable (epsilon = 0) and the correlati on function of early-type galaxies is steeper than that of spirals. We do not detect a significant cross-correlation between the radio galax ies and the other galaxies in these fields. The upper limits on the cr oss-correlation are consistent with a mean clustering environment of A bell class 0 for z similar to 1.1 radio galaxies, similar to that obse rved for radio galaxies at z similar to 0.5, but would argue against a n Abell class 1 or richer environment. As Abell 0 clustering around th e radio galaxies would not significantly increase the omega(theta) amp litude of galaxies in these fields, stable clustering with a steep xi( r) for E/SO galaxies appears to remain the most likely interpretation of the omega(theta) amplitude. At K less than or equal to 20, the numb er of galaxy-galaxy pairs of 2-3 arcsec separation exceeds the random expectation by a factor of 2.15+/-0.26. The excess of close pairs is c omparable to that previously reported for R-band data, and consistent with a similar to(1 + z)(2) evolution of the galaxy merger rate.