$\kappa$TNG: Effect of Baryonic Processes on Weak Lensing with
  IllustrisTNG Simulations
  We study the effect of baryonic processes on weak lensing (WL) observables
with a suite of mock WL maps, the $\kappa$TNG, based on the cosmological
hydrodynamic simulations IllustrisTNG. We quantify the baryonic effects on the
WL angular power spectrum, one-point probability distribution function (PDF),
and number counts of peaks and minima. We also show the redshift evolution of
the effects, which is a key to distinguish the effect of baryons from
fundamental physics such as dark energy, dark matter, and massive neutrinos. We
find that baryonic processes reduce the small-scale power, suppress the tails
of the PDF, peak and minimum counts, and change the total number of peaks and
minima. We compare our results to existing semi-analytic models and
hydrodynamic simulations, and discuss the source of discrepancies. The
$\kappa$TNG suite includes 10,000 realisations of $5 \times 5 \,
\mathrm{deg}^2$ maps for 40 source redshifts up to $z_s = 2.6$, well covering
the range of interest for existing and upcoming weak lensing surveys. We also
produce the $\kappa$TNG-Dark suite of maps, generated based on the
corresponding dark matter only IllustrisTNG simulations. Our mock maps are
suitable for developing analytic models that incorporate the effect of baryons,
but also particularly useful for studies that rely on mass maps, such as
non-Gaussian statistics and machine learning with convolutional neural
networks. The suite of mock maps is publicly available at Columbia Lensing
(http://columbialensing.org).
