The Hubble constant from SN Refsdal

On December 2015, Hubble Space Telescope (HST) observations detected the expected fifth counter image of SN Refsdal at z = 1:49. In [33], we compare the time delay predictions from numerous models with the measured value derived by [16] from very early data in the light curve of the SN Refsdal, and find a best value for H0 = 64+9 (68% CL), in excellent agreement with predictions from CMB and recent weak lensing data + BAO + BBN (from the DES Collaboration). This is the first constraint on H0 derived from time delays between multiple lensed SN images, and the first with a galaxy cluster lens, so subject to systematic effects different from other time delay H0 estimates. Additional time delay measurements from new multiply-imaged SNe will allow derivation of competitive constraints on H0.