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Main Authors: Rubira, Henrique, Conteddu, Francesco
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2504.18245
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author Rubira, Henrique
Conteddu, Francesco
author_facet Rubira, Henrique
Conteddu, Francesco
contents The multi-tracer (MT) technique has been shown to outperform single-tracer analyses in the context of galaxy clustering. In this paper, we conduct a series of Fisher analyses to further explore MT information gains within the framework of non-linear bias expansion. We examine how MT performance depends on the bias parameters of the subtracers, showing that directly splitting the non-linear bias generally leads to smaller error bars in $A_s$, $h$, and $ω_{\rm cdm}$ compared to a simple split in $b_1$. This finding opens the door to identifying subsample splits that do not necessarily rely on very distinct linear biases. We discuss different total and subtracer number density scenarios, as well as the possibility of splitting into more than two tracers. Additionally, we consider how different Fingers-of-God suppression scales for the subsamples can be translated into different $k_{\rm max}$ values. Finally, we present forecasts for ongoing and future galaxy surveys.
format Preprint
id arxiv_https___arxiv_org_abs_2504_18245
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multi-tracer beyond linear theory
Rubira, Henrique
Conteddu, Francesco
Cosmology and Nongalactic Astrophysics
The multi-tracer (MT) technique has been shown to outperform single-tracer analyses in the context of galaxy clustering. In this paper, we conduct a series of Fisher analyses to further explore MT information gains within the framework of non-linear bias expansion. We examine how MT performance depends on the bias parameters of the subtracers, showing that directly splitting the non-linear bias generally leads to smaller error bars in $A_s$, $h$, and $ω_{\rm cdm}$ compared to a simple split in $b_1$. This finding opens the door to identifying subsample splits that do not necessarily rely on very distinct linear biases. We discuss different total and subtracer number density scenarios, as well as the possibility of splitting into more than two tracers. Additionally, we consider how different Fingers-of-God suppression scales for the subsamples can be translated into different $k_{\rm max}$ values. Finally, we present forecasts for ongoing and future galaxy surveys.
title Multi-tracer beyond linear theory
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2504.18245