Tuesday

I present an investigation into the dust attenuation law at z=5 using the synthetic spectral energy distributions (SEDs) of N=498 simulated galaxies at z=5, taken from the First Billion Years (FiBY) simulation.
Using a set of empirical dust attenuation models, the parameters which best reproduce the observed z=5 luminosity function (LF) and color-magnitude relation (CMR) are explored, and I show how a simple model in which the dust optical depth is a linearly increasing function of stellar mass, and the dust attenuation slope is similar to the Calzetti law, can successfully reproduce the LF and CMR over a wide range of stellar population synthesis model (SPS) assumptions, including the effects of massive binaries.
No evidence is found for reddening slopes as steep as the Small Magellanic Cloud (SMC) extinction curve, as has been suggested by recent ALMA observations.
Finally, I discuss how these models are consistent with recent 1.3mm ALMA observations of the Hubble Ultra Deep Field (HUDF).