KiDS+VIKING-450 and DES-Y1 combined: Mitigating baryon feedback
  uncertainty with COSEBIs
  We present cosmological constraints from a joint cosmic shear analysis of the
Kilo-Degree Survey (KV450) and the Dark Energy Survey (DES-Y1), conducted using
Complete Orthogonal Sets of E/B-Integrals (COSEBIs). With COSEBIs we isolate
any B-modes which have a non-cosmic shear origin and demonstrate the robustness
of our cosmological E-mode analysis as no significant B-modes are detected. We
highlight how COSEBIs are fairly insensitive to the amplitude of the non-linear
matter power spectrum at high $k$-scales, mitigating the uncertain impact of
baryon feedback in our analysis. COSEBIs, therefore, allow us to utilise
additional small-scale information, improving the DES-Y1 joint constraints on
$S_8=\sigma_8(\Omega_{\rm m}/0.3)^{0.5}$ and $\Omega_{\rm m}$ by $20\%$.
Adopting a flat $\Lambda$CDM model we find $S_8=0.755^{+0.019}_{-0.021}$, which
is in $3.2\sigma$ tension with the Planck Legacy analysis of the cosmic
microwave background.
