3D-HST Emission Line Galaxies at z ~ 2: Discrepancies in the Optical/UV
  Star Formation Rates
  We use Hubble Space Telescope near-IR grism spectroscopy to examine the
H-beta line strengths of 260 star-forming galaxies in the redshift range 1.90 <
z < 2.35. We show that at these epochs, the H-beta star formation rate (SFR) is
a factor of ~1.8 higher than what would be expected from the systems'
rest-frame UV flux density, suggesting a shift in the standard conversion
between these quantities and star formation rate. We demonstrate that at least
part of this shift can be attributed to metallicity, as H-beta is more greatly
enhanced in systems with lower oxygen abundance. This offset must be considered
when measuring the star formation rate history of the universe. We also show
that the relation between stellar and nebular extinction in our z ~ 2 sample is
consistent with that observed in the local universe.
