25.01.2022 (Tuesday)

Is the Hubble constant a constant?

Regular Seminar Eoin Colgain (Sogang University)

at:
14:00 IC
room Online
abstract:

In recent years Adam Riess' SH0ES collaboration has made it fashionable to question Lambda-CDM through a series of steadily more precise local determinations of the Hubble constant, the latest of which currently stands at H0 = 73 ± 1 km/s/Mpc. On the other hand, questioning the FLRW paradigm is still taboo. However, if there is a 5 sigma discrepancy with Planck, then a good explanation is required. In the talk, I will explain why H0 should be bounded above by H0 ~ 71 km/s/Mpc in any FLRW cosmology, before presenting some observations that appear to challenge the working FLRW assumption that the Universe is isotropic and homogeneous. Time permitting, I will spell out the implications of a higher local H0 for dark energy models.