The Host Galaxies of Three Radio‐loud Quasars: 3C 48, 3C 345, and B2 1425+267

Observations with the Wide-Field/Planetary Camera-2 of the Hubble Space Telescope are presented for three radio-loud quasars: 3C 48 ( z = 0.367), B2 1425+267 ( z = 0.366), and 3C 345 ( z = 0.594). All three quasars have luminous (~4 × L *) galaxies as hosts, which are either elliptical (B2 1425+267 and 3C345) or interacting (3C 48), and all hosts are 0.5-1.0 mag bluer in V - I than other galaxies with the same overall morphology at redshifts similar to those of the quasars. The host of 3C 48 has many H II regions and a very extended tidal tail. All nine of the radio-loud quasars studied here and in a previous paper by Bahcall et al. either have bright elliptical hosts or occur in interacting systems. There is a robust correlation between the radio emission of the quasar and the luminosity of host galaxy; the radio-loud quasars reside in galaxies that are on average ~1 mag brighter than hosts of the radio-quiet quasars.