Mapping Large Scale Structure tracers onto the Dark Matter cosmic web

Dark matter, galaxies and the intergalactic medium form on large scales a filamentary pattern, called cosmic web. In this context, collapsed structures, such as galaxies, galaxy clusters and dark matter halos, reside preferentially in overdense regions of the matter density field and are hence, regarded as tracers of the underlying dark matter distribution. In this work we apply the BAM method to obtain the bias mapping relation between the dark matter density field and the Large Scale Structure tracers, and ultimately to sample accurate mock catalogs. In the first part, we extract the halo bias relation in a stochastic sense from dark matter only N-body cosmological simulations, the MINERVA suite. We find that a proper re-definition of the cosmic web, dubbed I-web and based on the invariants of the tidal field tensor, allows to sample halo mock catalogs with unprecedented accuracy in the 2- and 3-point statistics. In the second part of the work BAM is applied to a zoom-in hydrodynamical simulation, to learn how to map ionized gas density, neutral hydrogen (HI) number density, temperature and optical depths onto the dark matter field. We explore the possibility of exploiting the mapping between various baryonic tracer fields and the baryonic cosmic web classification, finding that the gas cosmic web carries more information on the spatial distribution of HI than the dark matter cosmic web. The final goal of these studies consists of sampling a great number of accurate mock catalogs of halos, IGM properties and Lyman-α forest fluxes, to be delivered to forthcoming surveys such as DESI, EUCLID, and J-PAS.