Systematics in Direct Measurements of the Hubble Constant

by Taylor Hoyt (Lawrence Berkeley National Laboratory; University of Chicago)

Wednesday 28 Jan 2026, 16:00 → 17:30 Europe/Zurich

Abstract:

The Hubble Tension is a seemingly significant discrepancy between empirically determined values of the universe’s present day expansion rate, referred to as the Hubble constant (H0), and the model-dependent value of H0 inferred from the characteristic acoustic fluctuations in the primordial universe. I will begin this talk by relaying the most important instances I have identified in direct measurements of H0 where systematics have been underestimated, particularly in the detector-level measurements of Cepheid variable stars and Type Ia supernovae, ultimately providing a sobering take on the significance of ongoing claims of new physics. I will also discuss instances where uncertainties in H0 have been more robustly estimated and validated. Finally, I will present future paths we can take to reduce systematics in H0. This talk is intended to be a free-flowing discussion, so input from the audience throughout the talk is encouraged.

 

Micro CV:

Taylor received his PhD in 2022 from the University of Chicago working with Prof. Wendy Freedman on measuring the Hubble constant, specializing in the Tip of the Red Giant Branch method for measuring extragalactic distances. He continued on to join the supernova cosmology group at Lawrence Berkeley National Laboratory where he has been expanding the scope of the group’s supernova analyses to include measurements of the Hubble constant.