The influence of feedback on the baryonic content of haloes in the COLIBRE simulations

Jonathan J. Davies; Joop Schaye; Filip Huško; Ruby J. Wright; Evgenii Chaikin; Matthieu Schaller; Robert J. McGibbon; Alejandro Benítez-Llambay; Sylvia Ploeckinger; Alexander J. Richings

arXiv · 2607.27319

The influence of feedback on the baryonic content of haloes in the COLIBRE simulations

Jonathan J. Davies·Joop Schaye·Filip Huško·Ruby J. Wright·Evgenii Chaikin·Matthieu Schaller·Robert J. McGibbon·Alejandro Benítez-Llambay·Sylvia Ploeckinger·Alexander J. Richings

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Abstract

We present predictions for the relation between the halo gas mass fraction and halo mass, $f_{\rm gas}^{200}-M_{200}$, from the COLIBRE cosmological simulations of galaxy formation, and explore how the gas content of haloes is influenced by feedback from supernovae and active galactic nuclei (AGN) over time. The $f_{\rm gas}^{200}-M_{200}$ relation in COLIBRE is non-monotonic, with a peak at $M_{200}\sim 10^{11.5-12}$~M$_\odot$. Below this mass, feedback from supernovae efficiently expels gas from the haloes of dwarf galaxies, and above it, AGN feedback efficiently depletes the haloes of galaxy groups. The fiducial COLIBRE model yields gas fractions for galaxy groups and clusters that agree with constraints from Chandra and XMM-Newton X-ray data, but which are high relative to gas fractions inferred from eROSITA stacks and measurements of the kinetic Sunyaev-Zel-dovich (kSZ) effect. COLIBRE's hybrid AGN feedback model, which combines thermal and jet-driven feedback, produces lower gas fractions in better agreement with eROSITA and kSZ measurements. COLIBRE produces lower gas fractions for groups and clusters than EAGLE and other contemporary simulations, and better agreement with observational constraints. We investigate the origin of this improvement relative to EAGLE, and how the resolution of the simulation affects the impact of feedback. Our results demonstrate that halo gas fractions are a sensitive probe of feedback physics, and that they can differ significantly between simulations that otherwise produce very similar galaxy populations.

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Jonathan J. Davies, Joop Schaye, Filip Huško, Ruby J. Wright, Evgenii Chaikin, Matthieu Schaller, Robert J. McGibbon, Alejandro Benítez-Llambay, Sylvia Ploeckinger, Alexander J. Richings. 2026-07-29. The influence of feedback on the baryonic content of haloes in the COLIBRE simulations. https://arxiv.org/abs/2607.27319

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