Presentation #552.03 in the session “Satellite Galaxies & Stellar Halos”.
The Carnegie-Chicago Hubble Program is recalibrating the cosmic distance ladder using Population II stars, providing an independent path to the local measurement of the Hubble constant. In this work, we determine the distance to the Fornax dwarf spheroidal galaxy using deep Hubble Space Telescope ACS/WFC observations as well as wide-field, ground-based imaging from the IMACS camera on the Magellan-Baade telescope. We present and compare three independent measurements of the distance modulus based on Population II stars, via the tip of the red giant branch (TRGB), RR Lyrae period-luminosity and period-Wesenheit relations, and the magnitude of the zero-age horizontal branch envelope. These measurements improve upon and are consistent with an extensive catalog of literature distances to Fornax, which we compile here.