Session
2025 Session 5
Location
Brigham Young University Engineering Building, Provo, UT
Start Date
5-5-2025 11:00 AM
Description
Many current observational methods to measure the expansion rate of the universe (H0) rely on the same zero-point calibrations. Values of the Hubble constant derived from those local calibrations are in conflict with the predicted value of H0 from the successful ΛCDM cosmological model, resulting in the "Hubble tension." In order to decrease systematic uncertainties, and to address this tension, we have created a new and independent sequence of distance measurement techniques. We have used James Webb Space Telescope (JWST) tip of the red giant branch (TRGB) distances to 14 giant elliptical galaxies that we used as calibrators for surface brightness fluctuation (SBF) distances. These TRGB distances replace the calibration previously occupied by Cepheid variable stars. We present a new calibration of the SBF distance scale using DECam optical colors and the TRGB zero point and show how it affects previous SBF measurements of the Hubble Constant.
The TRGB–SBF Project: Creating a New Distance Ladder With Surface Brightness Fluctuations
Brigham Young University Engineering Building, Provo, UT
Many current observational methods to measure the expansion rate of the universe (H0) rely on the same zero-point calibrations. Values of the Hubble constant derived from those local calibrations are in conflict with the predicted value of H0 from the successful ΛCDM cosmological model, resulting in the "Hubble tension." In order to decrease systematic uncertainties, and to address this tension, we have created a new and independent sequence of distance measurement techniques. We have used James Webb Space Telescope (JWST) tip of the red giant branch (TRGB) distances to 14 giant elliptical galaxies that we used as calibrators for surface brightness fluctuation (SBF) distances. These TRGB distances replace the calibration previously occupied by Cepheid variable stars. We present a new calibration of the SBF distance scale using DECam optical colors and the TRGB zero point and show how it affects previous SBF measurements of the Hubble Constant.