Resolving the intergalactic medium with tomographic reconstructions

Tue, May 05, 2015

Despite keen interest in how clusters form, the study of early cluster formation is observationally limited: clusters are rare and surveying large volumes is expensive. Today, there are only a handful of known z > 2 protoclusters. At the same time, cosmic voids have received renewed interest as tracers for an AP test and testing modified-gravity models, but current void samples are limited to z < 1. I will discuss how we can use densely packed Lyman-alpha forest sightlines to directly map large scale structure at z = 2 – 3, and how we can find protoclusters and voids using the maps. Using our new Wiener Filter code on sightlines with average separations of 2 – 3 Mpc/h, we can create high-quality maps of the IGM. With a resolution of a few Mpc, the maps clearly pick up protoclusters and voids, both with radii of up to 10 Mpc/h at z = 2.5. I will present the characteristic signals of these objects in the maps and forecasts for samples in upcoming surveys.