Figuring Out Gas & Galaxies in Enzo (FOGGIE). II. Emission from the z=3
  Circumgalactic Medium
  Observing the circumgalactic medium (CGM) in emission provides 3D maps of the
spatial and kinematic extent of the gas that fuels galaxies and receives their
feedback. We present mock emission-line maps of highly resolved CGM gas from
the FOGGIE project (Figuring Out Gas & Galaxies in Enzo) and link these maps
back to physical and spatial properties of the gas. By increasing the spatial
resolution alone, the total luminosity of the line emission increases by an
order of magnitude. This increase arises in the abundance of dense small-scale
structure resolved when the CGM gas is simulated to < 100 pc scales. Current
integral field unit instruments like KCWI and MUSE should be able to detect the
brightest knots and filaments of such emission, and from this to infer the bulk
kinematics of the CGM gas with respect to the galaxy. We conclude that
accounting for small-scale structure well below the level of instrument spatial
resolution is necessary to properly interpret such observations in terms of the
underlying gas structure driving observable emission.
