Speaker
Description
Persistent tension between low-redshift observations and the Cosmic Microwave Background radiation (CMB) suggests residual systematics or new physics beyond the standard LCDM model. Local observations of baryon acoustic oscillations with low-redshift distance calibrators can constrain the value of the Hubble constant and the sound horizon in a cosmologically independent way. When compared to the values inferred from the CMB, a tension up to 5 sigma arises. Several modifications of LCDM, either before or after recombination, have been put forward to reconcile the tension, but it is not clear how well these models actually perform. In my presentation, I will talk about the current status of tensions between the CMB-based and local (based on gravitational time delays and classical distance ladder) distance calibrations. I will also critically review most popular extensions of LCDM proposed to reconcile these measurements.
