Taming assembly bias for primordial non-Gaussianity

Abstract Primordial non-Gaussianity of the local type induces a strong scale-dependent bias on the clustering of halos in the late-time Universe. This signature is particularly promising to provide constraints on the non-Gaussianity parameter f NL from galaxy surveys, as the bias amplitude grows wit...

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Published inJournal of cosmology and astroparticle physics Vol. 2024; no. 2; pp. 48 - 85
Main Authors Fondi, Emanuele, Verde, Licia, Villaescusa-Navarro, Francisco, Baldi, Marco, Coulton, William R., Jung, Gabriel, Karagiannis, Dionysios, Liguori, Michele, Ravenni, Andrea, Wandelt, Benjamin D.
Format Journal Article
LanguageEnglish
Published Bristol IOP Publishing 01.02.2024
Institute of Physics (IOP)
Subjects
Amplitudes
Assembly
Astrophysics
Bias
Clustering
Constraints
cosmological parameters from LSS
cosmological simulations
Galaxies
galaxy surveys
inflation
Large scale structure of the universe
Parameters
Physics
Systematic errors
cosmological simulations
cosmological parameters from LSS
inflation
galaxy surveys
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Summary:Abstract Primordial non-Gaussianity of the local type induces a strong scale-dependent bias on the clustering of halos in the late-time Universe. This signature is particularly promising to provide constraints on the non-Gaussianity parameter f NL from galaxy surveys, as the bias amplitude grows with scale and becomes important on large, linear scales. However, there is a well-known degeneracy between the real prize, the f NL parameter, and the (non-Gaussian) assembly bias i.e., the halo formation history-dependent contribution to the amplitude of the signal, which could seriously compromise the ability of large-scale structure surveys to constrain f NL . We show how the assembly bias can be modeled and constrained, thus almost completely recovering the power of galaxy surveys to competitively constrain primordial non-Gaussianity. In particular, studying hydrodynamical simulations, we find that a proxy for the halo properties that determine assembly bias can be constructed from photometric properties of galaxies. Using a prior on the assembly bias guided by this proxy degrades the statistical errors on f NL only mildly compared to an ideal case where the assembly bias is perfectly known. The systematic error on f NL that the proxy induces can be safely kept under control.
ISSN:1475-7516
1475-7508
1475-7516
DOI:10.1088/1475-7516/2024/02/048