A Multiwavelength Study of Stephan’s Quintet

Stephan's Quintet (SQ) is a compact group that we find in an atypical momentwhen a high velocity intruder is passing through it. The intrusion isparticularly interesting because a previous intruder had stripped most of thegas from the group members. This debris field was shocked in the ongoingcollision with the new intruder. This evolutionary history agrees well withobservations and explains how a strongly interacting system can show low levelsof star formation. We present new multiwavelength data including previouslyunpublished ROSAT X-ray, Ha interference filter/FP, ISO MIR/FIR and radio lineand continuum images. These observations and previously published data providenew insights as well as support for some previous hypotheses. 1) FP and HIvelocities allow us to unambiguously distinguish between gas associated with SQand the new intruder. 2) Most detected emission regions are found in the remnant ISM of the NIwhich allows us to infer its size and present physical state. 3) The fewemission regions associated with the stripped ISM of SQ include the bestcandidate tidal dwarf galaxy. 4) Multiwavelength data suggest that strongMIR/FIR emission from the Seyfert 2 nucleus of NGC7319 comes from dust heateddirectly by a power-law continuum rather than a starburst. 5) Thecorrespondance between extended X-ray/radio continuum/forbidden opticalemission confirms the existence of a large scale shock in SQ.Comment: In press in AJ. 44 pages, 10 Postscript figures, uses aastex.st