Hunting Diffuse Galaxies with Next Generation Imaging Surveys

We are entering a new era for deep wide-field imaging surveys, which promises to extend our census of the galaxy population to lower surface brightnesses than has ever been possible over large areas of the sky. These surveys will uncover low surface brightness (LSB) galaxies across halo environments, which will provide important tests for theoretical predictions of galaxy and star formation, stellar feedback processes, and the distribution and nature of dark matter. I will present results from our ongoing efforts to discover and characterize diffuse galaxies with the Hyper Suprime-Cam Survey, a new generation imaging survey that is serving as a stepping stone into the LSST era. We are uncovering a diverse population of objects, spanning dwarf ellipticals in nearby galaxy groups to ultra-diffuse galaxies in the field to giant LSB spirals. Importantly, reliable distances are required to study the numbers and physical properties of these objects as a function of environment, and we are taking a number of approaches to constrain the distance distribution of our sample. I will focus in particular on our efforts to use the globular cluster luminosity function and ground-based surface brightness fluctuations as distance indicators. Pushing such studies to lower surface brightnesses will be necessary to form a more complete census of the galaxy population, which will ultimately provide one of the strongest tests of the standard LCDM framework.

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