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Bibliographic Details
Main Author: Banerjee, Arka
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2604.00097
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author Banerjee, Arka
author_facet Banerjee, Arka
contents Halo bias is typically treated as a set of coefficients in a perturbative expansion. We show instead that every point in a Gaussian density field has a well-defined scale-independent Lagrangian bias, thereby defining a bias field. This property can be extended to any linear operator acting on the Lagrangian density field, generating secondary bias fields. Halo bias then arises from geometric selection of Lagrangian patches within this pre-existing field, rather than being generated by collapse. We demonstrate that this framework predicts the measured $b(M)$ relation for halos. The multivariate Gaussian structure of the fields naturally explains the Gaussian distribution of halo bias at fixed mass and assembly bias. The results presented here motivate combining this framework with a forward model of halo collapse, yielding an ab initio model for halo clustering.
format Preprint
id arxiv_https___arxiv_org_abs_2604_00097
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Lagrangian Bias as a Gaussian Random Field
Banerjee, Arka
Cosmology and Nongalactic Astrophysics
Halo bias is typically treated as a set of coefficients in a perturbative expansion. We show instead that every point in a Gaussian density field has a well-defined scale-independent Lagrangian bias, thereby defining a bias field. This property can be extended to any linear operator acting on the Lagrangian density field, generating secondary bias fields. Halo bias then arises from geometric selection of Lagrangian patches within this pre-existing field, rather than being generated by collapse. We demonstrate that this framework predicts the measured $b(M)$ relation for halos. The multivariate Gaussian structure of the fields naturally explains the Gaussian distribution of halo bias at fixed mass and assembly bias. The results presented here motivate combining this framework with a forward model of halo collapse, yielding an ab initio model for halo clustering.
title Lagrangian Bias as a Gaussian Random Field
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2604.00097