  A complete understanding of Gamma Ray Bursts (GRBs) has been difficult to
achieve due to our incomplete knowledge of the radiation mechanism that is
responsible for producing the prompt emission. This emission, which is detected
in the first tens of seconds of the GRB, is typically dominated by hard X-ray
and gamma ray photons although, there have also been a few dozen prompt optical
detections. These optical detections have the potential to discriminate between
plausible prompt emission models, such as the photospheric and synchrotron
shock models. In this work we use an improved MCRaT code, which includes
cyclo-synchrotron emission and absorption, to conduct radiative transfer
calculations from optical to gamma ray energies under the photospheric model.
The calculations are conducted using a set of two dimensional relativistic
hydrodynamic long GRB jet simulations, consisting of a constant and variable
jet. We predict the correlations between the optical and gamma ray light curves
as functions of observer angle and jet variability and find that there should
be extremely dim optical prompt precursors for large viewing angles.
Additionally, the detected optical emission originates from dense regions of
the outflow such as shock interfaces and the jet-cocoon interface. Our results
also show that the photospheric model is not able to account for the current
set of optical prompt detections that have been made and additional radiative
mechanisms are needed to explain these prompt optical observations. These
findings show the importance of conducting global radiative transfer
simulations using hydrodynamically calculated jet structures.
