Faint structures around NGC 1549-53

NGC 1549-53
One of the biggest surprises to emerge from the application of the photographic amplification process was the detection of faint shells around otherwise apparently normal (but often isolated) elliptical galaxies. These faint traces are thought to be evidence of ancient mergers.>

The shell-like structures around this otherwise undistinguished pair NGC 1549 and 1553 were also unexpected, and suggest that interaction rather than merger could also generate structures of this kind. These galaxies were listed in the Malin-Carter catalogue of ellipticals with shells.
Original plates taken with the UK Schmidt Telescope