Stephan's Quintet
images from Xu etal 1999
Optical
ISOCAM LW3
Starburst may be occuring at interface between galaxy and hot intragroup medium.
Compare:
optical (greyscale),
Xray (black contours),
radio continuum (white contours)
radio: van der Hulst & Rots 1981
Xray: Pietsch etal 1997