PPT Slide
This region of the sky is highly overdense in Ly-alpha sources, red objects and gas. According to models, this must therefore be a many-sigma peak in the primordial density field: the ancestor of a rich cluster today.
The size and overdensity of this cluster are comparable to the Ly-break clusters seen by Mauro et al. While our observational techniques have been quite different from theirs, it seems probable that our cluster and theirs are members of the same class. If so, this implies that the properties inferred here could be ubiquitous in the early universe.