Assembly bias in quadratic bias parameters of dark matter halos from forward modeling

Lazeyras, Titouan; Barreira, Alexandre and Schmidt, Fabian (2021): Assembly bias in quadratic bias parameters of dark matter halos from forward modeling. In: Journal of Cosmology and Astroparticle Physics, No. 10, 63

Abstract

We use the forward modeling approach to galaxy clustering combined with the likelihood from the effective-field theory of large-scale structure to measure assembly bias, i.e. the dependence of halo bias on properties beyond the total mass, in the linear (b(1)) and second order bias parameters (b(2) and b(K2)) of dark matter halos in N-body simulations. This is the first time that assembly bias in the tidal bias parameter b(K2) is measured. We focus on three standard halo properties: the concentration c, spin A, and sphericity s, for which we find an assembly bias signal in b(K2) that is opposite to that in b(1). Specifically, at fixed mass, halos that get more (less) positively biased in b(1), get less (more) negatively biased in b(K2). We also investigate the impact of assembly bias on the b(2)(b(1)) and b(K2)(b(1)) relations, and find that while the b(2)(b(1)) relation stays roughly unchanged, assembly bias strongly impacts the bK(2)(b(1)) relation. This impact likely extends also to the corresponding relation for galaxies, which motivates future studies to design better priors on b(K2)(b(1)) for use in cosmological constraints from galaxy clustering data.

• Item Type: Journal article
• Faculties: Physics
• Subjects: 500 Science > 530 Physics
• ISSN: 1475-7516
• Language: English