Dr. Daniel McIntosh
Department of Physics
University of Missouri-Kansas City
Monday, March 8, 2010
Cosmic Collisions and Galaxy Evolution
Our understanding of the universe is intimately tied to our study of galaxies. As fundamental building blocks of baryonic matter, galaxies are beacons that illuminate the history of an otherwise dark matter and dark energy dominated cosmos. Examples of galaxies caught mid-collision, and differences in galaxy populations over cosmic time, both provide evidence that the universe is changing. Based on unprecedented galaxy samples from modern surveys, it is now clear that billions of years of star formation and mass assembly have produced a bimodal population of red and blue galaxies with unique characteristics. I will broadly outline how a growing but non-star-forming population of red spheroids, and a star-forming yet static population of blue disks, suggest connected evolutionary histories and have resulted in modifications of our current theories. In the context of our standard cosmological model, major interactions between galaxies of comparable mass are dramatic examples of hierarchical structure formation and are a leading explanation for the formation of large spheroids. To this end, I will focus on our understanding of the role that major merging plays in producing galaxy bimodality.