Modeling Galaxies in Redshift Space at the Field Level
  We develop an analytical forward model based on perturbation theory to
predict the redshift-space galaxy overdensity at the field level given a
realization of the initial conditions. We find that the residual noise between
the model and simulated galaxy density has a power spectrum that is white on
large scales, with size comparable to the shot noise. In the mildly nonlinear
regime, we see a $k^2\mu^2$ correction to the noise power spectrum,
corresponding to larger noise along the line of sight and on smaller scales.
The parametric form of this correction has been predicted on theoretical
grounds before, and our simulations provide important confirmation of its
presence. We have also modeled the galaxy velocity at the field-level and
compared it against simulated galaxy velocities, finding that about $10\%$ of
the galaxies are responsible for half of the rms velocity residual for our
simulated galaxy sample.
