The Photometric Properties of Galaxies in the Early Universe
  We use the large cosmological hydro-dynamic simulation BlueTides to predict
the photometric properties of galaxies during the epoch of reionisation
($z=8-15$). These properties include the rest-frame UV to near-IR broadband
spectral energy distributions, the Lyman continuum photon production, the UV
star formation rate calibration, and intrinsic UV continuum slope. In
particular we focus on exploring the effect of various modelling assumptions,
including the assumed choice of stellar population synthesis model, initial
mass function, and the escape fraction of Lyman continuum photons, upon these
quantities. We find that these modelling assumptions can have a dramatic effect
on photometric properties leading to consequences for the accurate
determination of physical properties from observations. For example, at $z=8$
we predict that nebular emission can account for up-to $50\%$ of the rest-frame
$R$-band luminosity, while the choice of stellar population synthesis model can
change the Lyman continuum production rate up to a factor of $\times 2$.
