Seminar

Cosmography with strong lensing time delays

By
Frédéric Courbin (Ecole Polytechnique Fédérale de Lausanne (EPFL))
Date
seminar ICCUB
Time delays in strong lensing lensed quasars and supernovae consist in a single-step probe to measure the Hubble constant in the local Universe. So far, results tend to support the value obtained with the distance ladder built from Cepheids and supernovae, but is in tension with the inverse distance ladder from CMB observations. Whether this tension is real, with profound consequences for Physics, or still dominated by observational uncertainties still has to be addressed carefully. I will review the field of time delay science, focusing on the results of the H0LiCOW and TDCOSMO collaborations, I will detail where we currently stand and what are the next steps to undertake to make advances. I will also show how a dedicated high-cadence 4m telescope with a 10-band imager along with a network of small telescopes operated with AI can revolutionize the field and act in full synergy with LSST, SKA and LIGO/Virgo.