Radio jets and bridges in the classical double sources 3C388 and 0816 + 526

Abstract

We report on 4885-MHz full synthesis high-resolution (1″) observations [using the NRAO Very Large Array (VLA)] of the ‘classical’ double radio sources 0816 + 526 and 3C388. Classical double sources are characterized by strong emission peaks (lobes) at the extremities of a linear structure. Although at lower resolution these sources both appear to have simple double-lobed morphologies, the VLA maps reveal several important new features. 0816 + 516 was found to have very sharp leading edges indicative of strong deceleration, possibly as a result of encountering a dense extragalactic background gas. The transverse boundaries of the components are also quite steep but still consistent with constant emissivity-filled cylinders rather than limb-brightening. The morphology of 3C388 is dramatically different from 0816 + 526, since it includes a bright radio jet. Unlike previously observed radio jets which are usually found between the nucleus of the radio galaxy and its extended lobes, the jet in 3C388 is embedded inside the southwestern lobe and a prominent gap in the radio emission exists between the radio nucleus and the beginning of the jet. These observations clearly illustrate that a variety of source substructures, which must be dealt with in theoretical models, exist within radio galaxies which were previously classified simply as classical doubles.