Simultaneously constraining cosmology and baryonic physics via deep
  learning from weak lensing
  Ongoing and planned weak lensing (WL) surveys are becoming deep enough to
contain information on angular scales down to a few arcmin. To fully extract
information from these small scales, we must capture non-Gaussian features in
the cosmological WL signal while accurately accounting for baryonic effects. In
this work, we account for baryonic physics via a baryonic correction model that
modifies the matter distribution in dark matter-only $N$-body simulations,
mimicking the effects of galaxy formation and feedback. We implement this model
in a large suite of ray-tracing simulations, spanning a grid of cosmological
models in $\Omega_\mathrm{m}-\sigma_8$ space. We then develop a convolutional
neural network (CNN) architecture to learn and constrain cosmological and
baryonic parameters simultaneously from the simulated WL convergence maps. We
find that in a Hyper-Suprime Cam (HSC)-like survey, our CNN achieves a
1.7$\times$ tighter constraint in $\Omega_\mathrm{m}-\sigma_8$ space ($1\sigma$
area) than the power spectrum and 2.1$\times$ tighter than the peak counts,
showing that the CNN can efficiently extract non-Gaussian cosmological
information even while marginalizing over baryonic effects. When we combine our
CNN with the power spectrum, the baryonic effects degrade the constraint in
$\Omega_\mathrm{m}-\sigma_8$ space by a factor of 2.4, compared to the much
worse degradation by a factor of 4.7 or 3.7 from either method alone.
