case western reserve university



Evolution of Spheroid Galaxies Over the Last Half of Cosmic History

Dan McIntosh (UMass)

I will show how large, modern surveys of galaxies are used to understand the evolution of spheroid systems over the last half of cosmic time. We find that galaxies with spheroid-dominated light profiles contain most of the stars in the present-day universe. The bulk of these stars formed before the universe was half its current age, yet many of the galaxies in which they reside were assembled more recently in major mergers between smaller galaxies. Concentrating on the spheroid population provides clues to overall galaxy evolution. The origin and evolution of galaxies is one of the main science drivers of NASA's Origins program, the planned James Webb Space Telescope, and most current and proposed large telescope and galaxy survey projects.