Globular Cluster Systems in Four Brightest Cluster Galaxies: A262, A3560, A3565, and A3742**Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposal ID 5910.

We have used deep I-band (F814W) images from the Hubble Space Telescope archive to study the globular cluster systems around the brightest cluster galaxies (BCGs) in A262, A3560, A3565, and A3742. Three of these BCGs have inner dust lanes and peculiar structural features that indicate past histories of low-level interaction and accretion. The deep I-band WFPC2 images have photometric limits that, for all four galaxies, reach near or just beyond the globular cluster luminosity function (GCLF) turnover point. Their specific frequencies are 8.24 ± 1.65, 4.66 ± 0.93, 2.58 ± 0.52, and 2.62 ± 0.52, respectively, all within a factor of 2 of the normal range for giant elliptical galaxies. We obtain new estimates of the GCLF turnover magnitudes, which are shown to be consistent with an adopted Hubble constant of H0 ≃ 70 km s-1 Mpc-1 on the "Hubble diagram" of GCLF turnover apparent magnitude versus redshift, on a distance scale where the fundamental GCLF calibrator E galaxies (M87 and others) in Virgo are at d = 16 Mpc.