The observational status of Stephan's Quintet

Abstract

We present new photometric and spectroscopic data for the galaxies in the compact group known as Stephan's Quintet. We find the strongest evidence for dynamical perturbation in the spiral component NGC 7319. Most of the damage was apparently caused by nearby NGC 7320C which passed through the group a few × 108 years ago. NGC 7318B is a spiral galaxy that shows evidence consistent with being in the early stages of a collision with the group. NGC 7317 and 18A are either elliptical galaxies or the stripped bulges of former spiral components. They show no evidence of past or present merger activity but are embedded in a luminous halo which suggests that they are interacting with the other members of the group. The low redshift galaxy NGC 7320 is most likely a late type, dwarf spiral projected along the same line of sight as the interacting quartet.