Book Description
Star formation is key to the regulation of galactic environments. Studying the sites of ongoing star formation is therefore critical to understanding the evolution of galaxies over cosmic time. Integral Field Spectrographs (IFS) have allowed astronomers to probe the dynamical processes of galaxies at high redshift, z∼1-3, revealing unique kiloparsec-scale "clumps" of star formation. The relationships between clump size, luminosity, and velocity dispersion are particularly important to understanding clump formation and evolution. These relationships have been measured in a variety of studies but disagreement remains about their nature and possible evolution with redshift. To investigate the cause of these differences, I collected a comprehensive sample of clump observations across redshifts and developed a Bayesian Markov Chain Monte Carlo fitting routine to robustly explore the scaling relationships of star-forming regions. There is evidence of a break into two clump populations based on their star formation rate surface density with differences in slope due to either the formation mode or geometry of the clump and host galaxy disk, but there is added uncertainty from limited observations at small clump sizes. To address this limitation, I observed a sample of compact H II regions in the local starburst galaxy, IC 10, with the Keck Cosmic Web Imager IFS at the W. M. Keck Observatory. I found these H II regions are offset to higher luminosity and velocity dispersion for a given size. These H II regions do not appear to be virialized, and instead show evidence that they are young and expanding. Even in the most compact H II regions, warm gas pressure from photoinization heating provides the dominant contribution to outward pressure and expansion. Improvements in instrumentation are also key to improving studies of the characteristics and evolution of star-forming regions, as well as many other astronomical objects. Liger, an adaptive optics fed IFS and imager for Keck Observatory, will provide improvements in resolution, field of view, and wavelength coverage compared to current instruments. I have developed the mechanical design of three major components of the Liger imager and sequential spectrograph: the filter wheel; selectable cold pupil stop; and mounting stage for the imager detector and IFS pick-off mirrors.
