The host galaxy and environment of the z=1.195 quasar 3C 190

We present deep imaging and spectroscopic observations of the z = 1.195 quasar 3C 190 and its immediate environment. The quasar is surrounded by an asymmetric, low surface brightness envelope in which there are also several galaxies with characteristic dimensions of 3-5 kpc. Some of these form a linear structure some 50 kpc long in projection, offset from the quasar and almost perpendicular to the radio axis. Spectroscopy of this feature indicates the presence of a starburst component, as well as stars a few hundred million years old. Velocities of the emission-line gas associated with H II regions in the linear feature are difficult to reconcile with any reasonable model that is also consistent with the observed morphology. One possible scenario is an edge-on disk in an extremely massive (similar to 10(12) M(.)) halo; another is two independent chain galaxies, with the apparent alignment being fortuitous. Taking into account all of the types of extended material we find in the vicinity of 3C 190, we appear to be witnessing a relatively brief phase in the development of a spheroidal galaxy, in which merging is proceeding nearly simultaneously in a variety of different regimes. This system may be one of the clearest examples yet found for the mechanism by which many elliptical galaxies and bulges of early-type spirals form in the early universe.