Abstract:
Current models predict that the z ~ 4-8 universe should be a time in which the most massive galaxies are transitioning from their initial halo assembly to the later baryonic evolution seen in star-forming galaxies and quasars.  Instead, massive galaxies appear to exist impossibly early, before their halos should even have been able to assemble.  We will consider hierarchical merging is truly inconsistent with observation or whether other explanations might be more likely.