•Cartwheel is an example we’ve already seen. Appear to result from small impact parameters.
•The core of the impacted galaxy can be pulled out entirely!
•The rings are kinematic waves. Companion temporarily draws stars into the center. Oscillations are set up and driven by disk gravity, and a density wave slowly propogates toward the outer part of the disk. Density waves cause star formation!
•Will examine some aspects of this in the homework.
Watch carefully!