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Main Authors: Zhan, Junhao, Reichardt, Christian L.
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.14464
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author Zhan, Junhao
Reichardt, Christian L.
author_facet Zhan, Junhao
Reichardt, Christian L.
contents We examine the potential improvements in constraints on the dark energy equation of state parameter $w$ and matter density $Ω_M$ from using clustering information along with number counts for future samples of thermal Sunyaev-Zel'dovich selected galaxy clusters. We quantify the relative improvement from including the clustering power spectrum information for three cluster sample sizes from 33,000 to 140,000 clusters and for three assumed priors on the mass slope and redshift evolution of the mass-observable relation. As expected, clustering information has the largest impact when (i) there are more clusters and (ii) the mass-observable priors are weaker. For current knowledge of the cluster mass-observable relationship, we find the addition of clustering information reduces the uncertainty on the dark energy equation of state, $σ(w)$, by factors of $1.023\pm 0.007$ to $1.0790\pm 0.011$, with larger improvements observed with more clusters. Clustering information is more important for the matter density, with $σ(Ω_M)$ reduced by factors of $1.068 \pm 007$ to $1.145 \pm 0.012$. The improvement in $w$ constraints from adding clustering information largely vanishes after tightening priors on the mass-observable relationship by a factor of two. For weaker priors, we find clustering information improves the determination of the cluster mass slope and redshift evolution by factors of $1.389 \pm 0.041$ and $1.340 \pm 0.039$ respectively. These findings highlight that, with the anticipated surge in cluster detections from next generation surveys, self-calibration through clustering information will provide an independent cross-check on the mass slope and redshift evolution of the mass-observable relationship as well as enhancing the precision achievable from cluster cosmology.
format Preprint
id arxiv_https___arxiv_org_abs_2510_14464
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Built-in precision: Improving cluster cosmology through the self-calibration of a galaxy cluster sample
Zhan, Junhao
Reichardt, Christian L.
Cosmology and Nongalactic Astrophysics
We examine the potential improvements in constraints on the dark energy equation of state parameter $w$ and matter density $Ω_M$ from using clustering information along with number counts for future samples of thermal Sunyaev-Zel'dovich selected galaxy clusters. We quantify the relative improvement from including the clustering power spectrum information for three cluster sample sizes from 33,000 to 140,000 clusters and for three assumed priors on the mass slope and redshift evolution of the mass-observable relation. As expected, clustering information has the largest impact when (i) there are more clusters and (ii) the mass-observable priors are weaker. For current knowledge of the cluster mass-observable relationship, we find the addition of clustering information reduces the uncertainty on the dark energy equation of state, $σ(w)$, by factors of $1.023\pm 0.007$ to $1.0790\pm 0.011$, with larger improvements observed with more clusters. Clustering information is more important for the matter density, with $σ(Ω_M)$ reduced by factors of $1.068 \pm 007$ to $1.145 \pm 0.012$. The improvement in $w$ constraints from adding clustering information largely vanishes after tightening priors on the mass-observable relationship by a factor of two. For weaker priors, we find clustering information improves the determination of the cluster mass slope and redshift evolution by factors of $1.389 \pm 0.041$ and $1.340 \pm 0.039$ respectively. These findings highlight that, with the anticipated surge in cluster detections from next generation surveys, self-calibration through clustering information will provide an independent cross-check on the mass slope and redshift evolution of the mass-observable relationship as well as enhancing the precision achievable from cluster cosmology.
title Built-in precision: Improving cluster cosmology through the self-calibration of a galaxy cluster sample
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2510.14464