The origin and evolution of galaxies

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I propose to investigate the evolution of galactic structures over cosmic time. This research will probe galaxies over a time range of about 11 billion years, which encompasses the major stellar mass-building phase of the universe. The central questions underlying the proposed research are: What did galaxies look like at high redshifts? How can we best describe these systems in a quantitative way? How does the Hubble Sequence emerge from these distant galaxies? How do changes in galactic structure map onto ideas for the underlying physics of galaxy evolution? The proposed research is complementary to investigations of very nearby galaxies in the Local Group (which focus on resolved stellar populations), and to investigations of galaxies at the highest redshifts at which they are known to exist. A central theme of the proposed research is the investigation of "red nuggets", an astonishing population of very compact massive evolved galaxies that appear to be about a factor of three smaller in the distant Universe than their closest nearby counterparts. These objects were discovered by my team several years ago, and my research seeks to better understand the mechanisms by which such galaxies grow in size. One way to understand the nature of these galaxies is to obtain detailed spectroscopy of them, which probes their ages, star-formation history and chemical composition. Another approach is to study them in the context of the general galaxy population, whose structure can now be described in far more detail than has been possible in the past, because of recent advances in machine vision. Technological advances in other areas are also driving this field forward. In particular, I will describe a how imaging of very faint structures in nearby galaxies can be used to test central predictions of galaxy formation models.