ABSTRACT

The vast majority of galaxies (by number) have prominent disks. Such disks are dynamically fragile, and would be strongly affected (or even disrupted) by interactions with other galaxies. Yet, one of the hallmarks of galaxy evolution in a dark-matter dominated Universe is that most galaxies should be subjected to an almost continuous rain of dark matter subhalos (many of them containing visible galaxies). In this talk, I show that i) many disk galaxies are indeed being destroyed and transformed into spheroidal galaxies in the last 8 billion years, arguably by interactions, and ii) those disk galaxies that remain bear the scars of a considerable beating by dwarf galaxies. I argue in the talk that these observations are consistent with our understanding of disk galaxy formation in a LCDM context, and I discuss a few key questions that will be the focus of the next few years of my research.