On the anisotropic density distribution on large scales

TL;DR

This paper presents a new formula for the anisotropic density distribution around cosmic structures, aligning well with simulations and challenging initial inertia-based models.

Contribution

The authors derive a linear theory-based formula for anisotropic density distribution that accounts for halo orientation and shear, improving understanding of large-scale structure.

Findings

The model agrees well with N-body simulation measurements.

The amplitude measurement contradicts initial inertia-based alignment models.

The formula enhances predictions of anisotropic clustering on large scales.

Abstract

Motivated by the recent detection of an enhanced clustering signal along the major axis of haloes in N-body simulations, we derive a formula for the anisotropic density distribution around haloes and voids on large scales. Our model, which assumes linear theory and that the formation and orientation of nonlinear structures are strongly correlated with the Lagrangian shear, is in good agreement with measurements. We also show that the measured amplitude is inconsistent with a model in which the alignment is produced by the initial inertia rather than shear tensor.