Inference from the small scales of cosmic shear with current and future
  Dark Energy Survey data
  Cosmic shear is sensitive to fluctuations in the cosmological matter density
field, including on small physical scales, where matter clustering is affected
by baryonic physics in galaxies and galaxy clusters, such as star formation,
supernovae feedback and AGN feedback. While muddying any cosmological
information that is contained in small scale cosmic shear measurements, this
does mean that cosmic shear has the potential to constrain baryonic physics and
galaxy formation. We perform an analysis of the Dark Energy Survey (DES)
Science Verification (SV) cosmic shear measurements, now extended to smaller
scales, and using the Mead et al. 2015 halo model to account for baryonic
feedback. While the SV data has limited statistical power, we demonstrate using
a simulated likelihood analysis that the final DES data will have the
statistical power to differentiate among baryonic feedback scenarios. We also
explore some of the difficulties in interpreting the small scales in cosmic
shear measurements, presenting estimates of the size of several other
systematic effects that make inference from small scales difficult, including
uncertainty in the modelling of intrinsic alignment on nonlinear scales,
`lensing bias', and shape measurement selection effects. For the latter two, we
make use of novel image simulations. While future cosmic shear datasets have
the statistical power to constrain baryonic feedback scenarios, there are
several systematic effects that require improved treatments, in order to make
robust conclusions about baryonic feedback.
