TARDIS Paper II: Synergistic Density Reconstruction from Lyman-alpha
  Forest and Spectroscopic Galaxy Surveys with Applications to Protoclusters
  and the Cosmic Web
  In this work we expand upon the Tomographic Absorption Reconstruction and
Density Inference Scheme (TARDIS) in order to include multiple tracers while
reconstructing matter density fields at Cosmic Noon (z ~ 2-3). In particular,
we jointly reconstruct the underlying density field from simulated Lyman-Alpha
forest observations at $z\sim 2.5$ and an overlapping galaxy survey. We find
that these data are synergistic, with the Lyman Alpha forest providing
reconstruction of low density regions and galaxy surveys tracing the density
peaks. We find a more accurate power spectra reconstruction going to higher
scales when fitting these two data-sets simultaneously than if using either one
individually. When applied to cosmic web analysis, we find performing the joint
analysis is equivalent to a Lyman Alpha survey with significantly increased
sight-line spacing. Since we reconstruct the velocity field and matter field
jointly, we demonstrate the ability to evolve the mock observed volume further
to z=0, allowing us to create a rigorous definition of "proto-cluster" as
regions which will evolve into clusters. We apply our reconstructions to study
protocluster structure and evolution, finding for realistic survey parameters
we can provide accurate mass estimates of the z \approx 2 structures and their
z = 0 fate.
