Tip of the Red Giant Branch Distances to Nearby Galaxies

Abstract

The tip of the red giant branch (TRGB) is becoming the preferred technique to determine accurate distances to galaxies within the local Universe. The method involves using the brightest red giant branch stars as standard candles, and has now been applied to nearly 500 galaxies within 20 Mpc. Accurate distances are essential for transforming observed properties of galaxies into their physical counterparts (luminosity, physical size, etc.). In addition to their inherent benefits, distances allow us to disentangle the two components of a galaxy’s observed velocity, the component due to the Hubble Flow, and its peculiar velocity. With the latter, we map the patterns of large-scale galaxy flows, and provide insight into the formation and evolution of large-scale structure. In this dissertation, I provide science highlights from the ongoing TRGB component of the Cosmicflows program, and showcase several recent results from this work.