Institute for Advanced Study/Princeton University Early Universe/Cosmology Lunch Discussion

Abstract 1: In this talk I will first briefly review recent developments in using forward modeling techniques combined with the likelihood from effective theory of large-scale structure to extract cosmological information from galaxy clustering. I will then present new results for halo assembly bias (i.e. the dependence of halo bias on properties beyond the total mass) in the linear and second order bias parameters obtained from the forward modeling approach. In particular, I will show the first measurements of assembly bias in the tidal bias parameter, as well as the impact of assembly bias on known relations between the second order parameters and the linear one. This impact likely extends also to the corresponding relation for galaxies, which motivates future studies to design better priors for use in cosmological constraints from galaxy clustering data. https://arxiv.org/abs/2106.14713.

Abstract 2: Abstract: Conventional probes of fundamental physics tend to consider one of three regimes: small scales, cosmological scales or the strong-field regime. Since LCDM is known to have several galactic-scale issues and novel physics (modified gravity, non-cold dark matter etc.) can alter galactic dynamics and morphology, tests of fundamental physics on astrophysical scales can provide tight constraints which are complementary to traditional techniques. By forward-modelling observational signals on a source-by-source basis and marginalising over models describing other astrophysical and observational processes, it is possible to harness the constraining power of galaxies whilst accounting for their complexity. In this talk I will demonstrate how these Bayesian Monte Carlo-based forward models can be used to constrain a variety of gravitational theories and outline ways to assess their robustness to baryonic effects.