How cluster pressure profiles scale: Mass, redshift, and intrinsic scatter
- 1INAF-Osservatorio Astronomico di Brera
Abstract
The thermal pressure profile of the intracluster medium is a critical component for cluster cosmology and for understanding the astrophysics of galaxy clusters. We aim to determine the population-averaged pressure profile of Sunyaev-Zel’dovich (SZ) selected galaxy clusters, characterize its intrinsic scatter, and measure its scaling with cluster mass and redshift. We selected a high-quality sample of 60 clusters from the South Pole Telescope (SPT) SZ catalog with 0.08 < z < 0.6, requiring a high signal-to-noise and five element resolution on Planck-SPT Compton-y maps. We extracted Compton-y maps and used a hierarchical Bayesian framework to model the spherical three-dimensional pressure profiles using restricted cubic splines. Crucially, we employed an updated weak-lensing-calibrated Compton-Y–mass scaling relation, effectively removing hydrostatic mass bias from the inferred masses. Our model is internally self-consistent, accommodating cluster-to-cluster profile variations and allowing the foreground and background contributions to vary between lines of sight. Furthermore, we allow for outliers arising from both bona fide clusters with intrinsically distinct profiles and line-of-sight projection effects. The code is made public available with this paper. We derive the population-averaged pressure profile and confirm that the intrinsic scatter is minimal at intermediate radii (0.4 ≤ r/r500 ≤ 0.7). Due to the adoption of the unbiased mass scaling, our derived pressure profile is approximately 40% lower than previous estimates at all radii. We find suggestive, though not conclusive, evidence that the currently adopted mass dependence may require revision specifically by canceling the additional M0.12 mass scaling introduced by Arnaud et al. (2010, A&A, 517, A92). We further constrain departures from self-similar evolution in the mean profile to be smaller than 0.1–0.2 dex and limit the evolution of the intrinsic scatter to less than 8 % per Δz = 0.1. Future work should assess the impact of this updated pressure-profile model on SZ observables, cluster mass calibration, survey completeness, thermal SZ power spectrum predictions, halo-model calculations, and cosmological parameter inference.
Related
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BibTeX
@article{andreon2026cluster,
title = {{How cluster pressure profiles scale: Mass, redshift, and intrinsic scatter}},
author = {Andreon S. and Castagna F.},
journal = {Astronomy \& Astrophysics},
year = {2026},
month = oct,
doi = {10.1051/0004-6361/202661620},
url = {https://doi.org/10.1051/0004-6361/202661620},
note = {CC BY},
}
RIS
TY - JOUR
TI - How cluster pressure profiles scale: Mass, redshift, and intrinsic scatter
AU - Andreon S.
AU - Castagna F.
PY - 2026
DA - 2026/10/23
JO - Astronomy & Astrophysics
DO - 10.1051/0004-6361/202661620
UR - https://doi.org/10.1051/0004-6361/202661620
AB - The thermal pressure profile of the intracluster medium is a critical component for cluster cosmology and for understanding the astrophysics of galaxy clusters. We aim to determine the population-averaged pressure profile of Sunyaev-Zel’dovich (SZ) selected galaxy clusters, characterize its intrinsic scatter, and measure its scaling with cluster mass and redshift. We selected a high-quality sample of 60 clusters from the South Pole Telescope (SPT) SZ catalog with 0.08 < z < 0.6, requiring a high signal-to-noise and five element resolution on Planck-SPT Compton-y maps. We extracted Compton-y maps and used a hierarchical Bayesian framework to model the spherical three-dimensional pressure profiles using restricted cubic splines. Crucially, we employed an updated weak-lensing-calibrated Compton-Y–mass scaling relation, effectively removing hydrostatic mass bias from the inferred masses. Our model is internally self-consistent, accommodating cluster-to-cluster profile variations and allowing the foreground and background contributions to vary between lines of sight. Furthermore, we allow for outliers arising from both bona fide clusters with intrinsically distinct profiles and line-of-sight projection effects. The code is made public available with this paper. We derive the population-averaged pressure profile and confirm that the intrinsic scatter is minimal at intermediate radii (0.4 ≤ r/r500 ≤ 0.7). Due to the adoption of the unbiased mass scaling, our derived pressure profile is approximately 40% lower than previous estimates at all radii. We find suggestive, though not conclusive, evidence that the currently adopted mass dependence may require revision specifically by canceling the additional M0.12 mass scaling introduced by Arnaud et al. (2010, A&A, 517, A92). We further constrain departures from self-similar evolution in the mean profile to be smaller than 0.1–0.2 dex and limit the evolution of the intrinsic scatter to less than 8 % per Δz = 0.1. Future work should assess the impact of this updated pressure-profile model on SZ observables, cluster mass calibration, survey completeness, thermal SZ power spectrum predictions, halo-model calculations, and cosmological parameter inference.
SN - 0004-6361
SN - 1432-0746
ER -