Lyman Alpha Absorption in The Cosmic Web

We describe large scale structure at high redshift in terms of the Cosmic Web picture for {S,Lambda,O,H}CDM models: how galactic-scale peak-patches'', filaments and membranes create an interconnected intergalactic medium. The ideas are applied to our Ly$\alpha$ forest simulations of shear-field patches’'. We discuss simulation method and design, resolution dependence, the statistical combination of patches, UV flux scaling, and whether filtered Zel’dovich maps are useful. The response to changes in power spectrum shape and amplitude, and in cosmological parameters, is described. We also show Omega_b h^2 derived from UV rescaling is overestimated if the resolution is not adequate.