%0 Journal Article %T KiDS+VIKING-450 and DES-Y1 combined: Cosmology with cosmic shear %A A. H. Wright %A A. Kannawadi %A B. Joachimi %A C. Heymans %A D. Traykova %A H. Hildebrandt %A H. Hoekstra %A J. L. van den Busch %A K. Kuijken %A L. Miller %A M. Asgari %A N. E. Chisari %A S. Joudaki %A T. Erben %A T. Tr£¿ster %J - %D 2020 %R 10.1051/0004-6361/201936154 %X We present a combined tomographic weak gravitational lensing analysis of the Kilo Degree Survey (KV450) and the Dark Energy Survey (DES-Y1). We homogenize the analysis of these two public cosmic shear datasets by adopting consistent priors and modeling of nonlinear scales, and determine new redshift distributions for DES-Y1 based on deep public spectroscopic surveys. Adopting these revised redshifts results in a 0.8¦̉ reduction in the DES-inferred value for S£¿8, which decreases to a 0.5¦̉ reduction when including a systematic redshift calibration error model from mock DES data based on the MICE2 simulation. The combined KV450+DES-Y1 constraint on is in tension with the Planck 2018 constraint from the cosmic microwave background at the level of 2.5¦̉. This result highlights the importance of developing methods to provide accurate redshift calibration for current and future weak-lensing surveys %U https://www.aanda.org/articles/aa/full_html/2020/06/aa36154-19/aa36154-19.html