What’s missing in AGN feedback: Lessons learnt from Magneticum, IllustrisTNG, and Simba
Le résumé fourni par la source
Accurately balancing gas reservoirs, star formation, and feedback processes across cosmic time remains one of the central challenges for galaxy formation models implemented in modern hydrodynamical simulations. While different feedback prescriptions can reproduce selected local galaxy properties with varying success, some of the most pronounced discrepancies emerge when comparing predictions for the hot gas content of dark matter halos. In this study, we examine three state-of-the-art cosmological simulations: Magneticum, IllustrisTNG, and SIMBA, which struggle to simultaneously reproduce the observed galaxy and halo gas properties in the local Universe. We confront their predictions with spatially resolved galaxy data from MaNGA and recent observational constraints on the hot gas mass fraction--halo mass (f_ gas --M_ h ) relation derived from eROSITA and Sunyaev--Zel'dovich measurements. Reproducing the observed relation f_ gas --M_ h requires strong active galactic nucleus (AGN) feedback. However, such strong feedback often leads to excessive quenching in simulated galaxy populations. Magneticum and SIMBA successfully match the observed gas fraction relation but predict an overabundance of quenched galaxies. In contrast, IllustrisTNG implements weaker AGN feedback, yielding more realistic star-forming fractions but systematically overpredicting hot gas masses in massive groups and poor clusters. In general, the stated tensions indicate that the current feedback models remain incomplete, not only in terms of the total energy injected but also in terms of the timing, location, and coupling of this energy to the surrounding gas. Our results therefore highlight the need to revisit subgrid feedback prescriptions and to develop more self-consistent models capable of simultaneously regulating galaxy growth and the thermodynamic properties of halo gas. Motivated by this discrepancy, a companion study will explore whether the feedback strengths required to match halo gas constraints inevitably lead to overquenching and distorted galaxy demographics.
Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.