First confirmation of anisotropic halo bias from statistically anisotropic matter distributions

TL;DR

This paper confirms the existence of anisotropic halo bias linked to statistical anisotropy in matter distributions, revealing mass-dependent effects that could test anisotropic universe models.

Contribution

First demonstration of anisotropic halo bias from matter distribution anisotropy using cosmological simulations, with implications for testing anisotropic inflation and dark energy models.

Findings

SA-induced bias coefficient is negative for cluster-sized halos

Bias decreases with increasing halo mass

Quadrupole halo power spectra are less amplified than monopole spectra

Abstract

We confirm for the first time the existence of distinctive halo bias associated with the quadrupolar type of statistical anisotropy (SA) of the linear matter density field using cosmological $N$-body simulations. We find that the coefficient of the SA-induced bias for cluster-sized halos takes negative values and exhibits a decreasing trend with increasing halo mass. This results in the quadrupole halo power spectra in a statistically anisotropic universe being less amplified compared to the monopole spectra. The anisotropic feature in halo bias that we found presents a promising new tool for testing the hypothesis of a statistically anisotropic universe, with significant implications for the precise verification of anisotropic inflation scenarios and vector dark matter and dark energy models.