Excursion set peaks: the role of shear

Abstract

Recent analytical work on the modelling of dark halo abundances and clustering has demonstrated the advantages of combining the excursion set approach with peaks theory. We extend these ideas and introduce a model of excursion set peaks that incorporates the role of initial tidal effects or shear in determining the gravitational collapse of dark haloes. The model -- in which the critical density threshold for collapse depends on the tidal influences acting on protohaloes -- is well motivated from ellipsoidal collapse arguments and is also simple enough to be analytically tractable. We show that the predictions of this model are in very good agreement with measurements of the halo mass function and traditional scale dependent halo bias in N-body simulations across a wide range of masses and redshift. The presence of shear in the collapse threshold means that halo bias is naturally predicted to be nonlocal, and that protohalo densities at fixed mass are naturally predicted to have Lognormal-like distributions. We present the first direct estimate of Lagrangian nonlocal bias in N-body simulations, finding broad agreement with the model prediction. Finally, the simplicity of the model (which has essentially a single free parameter) opens the door to building efficient and accurate non-universal fitting functions of halo abundances and bias for use in precision cosmology.

arXiv comment17 pages, 13 figures, submitted to MNRAS

References in corpus (1)

• The formation of CDM haloes II: collapse time and tides

Cited by in corpus (22)

• Galaxy evolution in the metric of the Cosmic Web
• Halo assembly bias and the tidal anisotropy of the local halo environment
• How does the cosmic web impact assembly bias?
• Beyond LIMD bias: a measurement of the complete set of third-order halo bias parameters
• Multi-tracer extension of the halo model: probing quenching and conformity in eBOSS
• Cosmic web anisotropy is the primary indicator of halo assembly bias
• Large-scale assembly bias of dark matter halos
• Halo bias in Lagrangian Space: Estimators and theoretical predictions
• DEMNUni: Massive neutrinos and the bispectrum of large scale structures
• Cosmic web dependence of galaxy clustering and quenching in SDSS
• COSMIC BIRTH: Efficient Bayesian Inference of the Evolving Cosmic Web from Galaxy Surveys
• Biased Tracers of Two Fluids in the Lagrangian Picture
• When do cosmic peaks, filaments or walls merge? A theory of critical events in a multi-scale landscape
• Taming assembly bias for primordial non-Gaussianity
• Renormalization of Lagrangian bias via spectral parameters
• Analytical halo models of cosmic tidal fields
• Deep learning insights into cosmological structure formation
• Consistency relations for the Lagrangian halo bias and their implications
• Tidal shear and the consistency of microscopic Lagrangian halo approaches
• Mass accretion rates and multi-scale halo environment in cold and warm dark matter cosmologies
• A fully Lagrangian, non-parametric bias model for dark-matter halos
• Assembly bias in quadratic bias parameters of dark matter halos from forward modeling