CHEX-MATE: Are we getting cluster thermodynamics right?
Abstract
Context. Galaxy clusters offer powerful insights into the large-scale structure of the Universe and the physics of baryons in hot states. Their scientific exploitation, however, hinges on our ability to accurately measure key thermodynamic properties. Aims. In this work we assess the reliability of current analysis techniques in reconstructing these properties, with a particular focus on samples similar to those observed in the Cluster Heritage project with XMM-Newton (CHEX-MATE). Methods. We developed a suite of dedicated end-to-end simulations of CHEX-MATE-like clusters selected from large-scale hydrodynamical simulations and processed through a newly developed realistic XMM-Newton simulator. We applied a full X-ray data analysis pipeline that includes imaging, spectral fitting, and profile reconstruction to the mock datasets. Results. The gas density profiles can be robustly recovered across a wide radial range when using azimuthal mean surface brightness profiles. Our reconstruction techniques are able to reproduce the intrinsic density profile with the correct scatter, with deviations of at most 10% between 0.1 and 1 × R 500c . The gas mass is reconstructed with better than 1% accuracy. The accurate measurement of temperature profiles is more challenging and possibly subject to biases, particularly in the presence of azimuthal variations and multi-temperature gas along the line of sight, which dominate over projection effects. Conclusions. Our results highlight the need for caution when interpreting cluster temperature measurements and underscore the value of tailored mock observations for understanding observational systematics. These findings also suggest that biases in X-ray temperature measurements alter the interpretation of the thermodynamical state of the intra-cluster medium, an outlook particularly relevant in light of recent low-velocity measurements from the XRISM mission.
Related
- CHEX-MATE: X-ray surface brightness discontinuities across a representative cluster sample
- CHEX-MATE: X-ray surface brightness discontinuities across a representative cluster sample
- CHEX-MATE: AMALGAM weak-lensing analysis of 41 Planck Sunyaev--Zel'dovich-selected galaxy clusters
- CHEX-MATE: Density profile reconstruction in galaxy clusters
- CHEX-MATE: Density profile reconstruction in galaxy clusters
BibTeX
@article{seppi2026chexmate,
title = {{CHEX-MATE: Are we getting cluster thermodynamics right?}},
author = {R. Seppi and D. Eckert and E. Rasia and S. Kay and K. Dolag and V. Biffi and Y. Bahar and H. Bourdin and F. de Luca and M. de Petris and S. Ettori and M. Gaspari and F. Gastaldello and V. Ghirardini and L. Lovisari and P. Mazzotta and G. Pratt and E. Pointecouteau and M. Rossetti and J. Sayers and M. Sereno and G. Yepes},
journal = {Astronomy \& Astrophysics - A\&A},
year = {2026},
month = jul,
doi = {10.1051/0004-6361/202558537},
url = {https://hal.science/hal-05762329v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - CHEX-MATE: Are we getting cluster thermodynamics right?
AU - R. Seppi
AU - D. Eckert
AU - E. Rasia
AU - S. Kay
AU - K. Dolag
AU - V. Biffi
AU - Y. Bahar
AU - H. Bourdin
AU - F. de Luca
AU - M. de Petris
AU - S. Ettori
AU - M. Gaspari
AU - F. Gastaldello
AU - V. Ghirardini
AU - L. Lovisari
AU - P. Mazzotta
AU - G. Pratt
AU - E. Pointecouteau
AU - M. Rossetti
AU - J. Sayers
AU - M. Sereno
AU - G. Yepes
PY - 2026
DA - 2026/07/16
JO - Astronomy & Astrophysics - A&A
DO - 10.1051/0004-6361/202558537
UR - https://hal.science/hal-05762329v1
AB - Context. Galaxy clusters offer powerful insights into the large-scale structure of the Universe and the physics of baryons in hot states. Their scientific exploitation, however, hinges on our ability to accurately measure key thermodynamic properties. Aims. In this work we assess the reliability of current analysis techniques in reconstructing these properties, with a particular focus on samples similar to those observed in the Cluster Heritage project with XMM-Newton (CHEX-MATE). Methods. We developed a suite of dedicated end-to-end simulations of CHEX-MATE-like clusters selected from large-scale hydrodynamical simulations and processed through a newly developed realistic XMM-Newton simulator. We applied a full X-ray data analysis pipeline that includes imaging, spectral fitting, and profile reconstruction to the mock datasets. Results. The gas density profiles can be robustly recovered across a wide radial range when using azimuthal mean surface brightness profiles. Our reconstruction techniques are able to reproduce the intrinsic density profile with the correct scatter, with deviations of at most 10% between 0.1 and 1 × R 500c . The gas mass is reconstructed with better than 1% accuracy. The accurate measurement of temperature profiles is more challenging and possibly subject to biases, particularly in the presence of azimuthal variations and multi-temperature gas along the line of sight, which dominate over projection effects. Conclusions. Our results highlight the need for caution when interpreting cluster temperature measurements and underscore the value of tailored mock observations for understanding observational systematics. These findings also suggest that biases in X-ray temperature measurements alter the interpretation of the thermodynamical state of the intra-cluster medium, an outlook particularly relevant in light of recent low-velocity measurements from the XRISM mission.
SN - 0004-6361
SN - 1432-0746
ER -