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Astrophysics Colloquium

The H0 Puzzle: Early vs. Late Time Resolutions
Presented by Bhuvnesh Jain
Department of Physics and Astronomy, University of Pennsylvania

Thursday, February 6, 2020
11:00 A.M. in 169-336

Abstract
The expansion rate H0 measured directly is significantly higher than inferred from cosmic microwave background measurements at high redshift. Possible resolutions to this puzzle generally involve new physics in the pre-recombination era. I will describe a low redshift resolution based on the Cepheid calibration of Supernova distances. Fifth forces due to unscreened scalar fields can modify the period-luminosity relation of Cepheids and alleviate the H0 tension. I will also discuss empirical progress on the sigma8 tension. I'll conclude with some highlights from cluster scale tests of dark matter and galaxy evolution.

JPL Contact: Olivier Dore (4-0690)


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