| Abstract: | These lectures discuss dynamically "hot" stellar systems --elliptical galaxies and the elliptical-galaxy-like "bulge" components of disk galaxies. The canonical picture of their origin is that they are made in collisions and mergers of roughly equal-mass galaxies. The resulting dynamical violence scrambles any pre-existing disks into ellipsoidal remnants, and it is accompanied by a central starburst if the progenitor galaxies contained cold gas. Our recent observations support these ideas but lead to a richer picture of galaxy evolution. We distinguish between galaxies that formed via mergers and ones that formed by other processes such as ram-pressure stripping of cold gas by hot, x-ray-emitting gas in galaxy clusters. We distinguish between ellipticals that formed by dry, cold-gas-free mergers and ones that involved gas dissipation and starbursts. And we can connect these events with supermassive black holes in galaxy centers. The results provide a comprehensive understanding of the structural properties that are encoded in the Hubble sequence of galaxies. Our latest results in this subject have just been submitted to ApJS: http://chandra.as.utexas.edu/~kormendy/parallel.pdf |
