Orateur
Description
The standard excursion set approach to dark matter halo formation typically evaluates local collapse without explicitly accounting for the cosmic-web geometry of the large-scale structure. In this talk, I will present a theoretical framework for halo and galaxy bias featuring explicit environmental dependence, inspired by the Web-Halo model. By physically conditioning halo collapse on cosmic web structures—such as sheets and filaments—this framework predicts higher-order and non-linear bias parameters with improved precision.
I will then explore the observational implications of this theoretical modeling for current large-scale structure surveys, focusing on the Dark Energy Spectroscopic Instrument (DESI). Current DESI full-shape and ShapeFit analyses rely heavily on the Effective Field Theory of Large-Scale Structure (EFTofLSS). A primary bottleneck is the necessity to marginalize over highly degenerate nuisance parameters, which dilutes the final cosmological constraining power. I will discuss how physically motivated, analytical priors derived from environmental bias models can effectively break these EFT degeneracies, offering a robust method to tighten cosmological constraints extracted from the broad-band power spectrum.