Entropy plateaus can emerge from gas replacement at a characteristic halo mass in simulated groups and clusters of galaxies

Abstract

The evolution of the intergalactic medium (IGM) is influenced by gravitational collapse, radiative cooling, and baryonic feedback. Using cosmological hydrodynamic zoom-in simulations of a $8.83\times 10^{12}$ M${}_{\odot }$ group and a $2.92\times 10^{14}$ M${}_{\odot }$ cluster at $z=0$, we investigate the emergence of entropy plateaus and their connection to feedback mechanisms. This set-up uses the SWIFT-EAGLE model with three resolutions, down to an initial particle gas mass of $2.29\times 10^5$ M${}_{\odot }$ and $1.23\times 10^6$ M${}_{\odot }$ for dark matter. We find that, when halos reach the characteristic mass of $\sim 10^{12}$ M${}_{\odot }$, their entropy profiles flatten at the virial radius, marking a transition from supernova to AGN feedback-driven regulation. As halos grow into groups ($\sim 10^{13}$ M${}_{\odot }$), the entropy plateau extends inward and isentropic cores form in massive systems ($\sim 10^{14}$ M${}_{\odot }$). By tracking the Lagrangian history of gas particles, we demonstrate that this entropy buildup is primarily driven by AGN feedback, which efficiently removes low-entropy gas from progenitors of groups and clusters, redistributing it throughout the IGM before falling into the core. Recent observations of X-GAP groups reveal large entropy excesses and plateaus, in line with our findings and in contrast to the power-law-like profiles of most previous observations. While entropy plateaus and large entropy excesses may be observationally confirmed in unbiased samples, reproducing the full diversity of entropy profiles remains an outstanding challenge for next-generation feedback models. Our results suggest that current feedback models may be overly efficient in expelling low-entropy gas from the potential cool-core progenitors, disrupting the balance between heating and cooling required for long-lived cool cores.

22 pages, 8 figures, 2 tables. Accepted for publication in MNRAS. Code, data, and documentation available at https://github.com/edoaltamura/entropy-core-evolution

References in corpus (35)

• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• Simba: Cosmological Simulations with Black Hole Growth and Feedback
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• The dark nemesis of galaxy formation: why hot haloes trigger black hole growth and bring star formation to an end
• The FLAMINGO project: cosmological hydrodynamical simulations for large-scale structure and galaxy cluster surveys
• Morphology and star formation in IllustrisTNG: the build-up of spheroids and discs
• Quasars Are Not Light-Bulbs: Testing Models of Quasar Lifetimes with the Observed Eddington Ratio Distribution
• The redshift evolution of massive galaxy clusters in the MACSIS simulations
• Radiative cooling rates, ion fractions, molecule abundances and line emissivities including self-shielding and both local and metagalactic radiation fields
• SWIFT: A modern highly-parallel gravity and smoothed particle hydrodynamics solver for astrophysical and cosmological applications
• Sphenix: Smoothed Particle Hydrodynamics for the next generation of galaxy formation simulations
• The evolution of clusters in the CLEF cosmological simulation: X-ray structural and scaling properties
• The fundamental signature of star formation quenching from AGN feedback: A critical dependence of quiescence on supermassive black hole mass not accretion rate
• The importance of black hole repositioning for galaxy formation simulations
• Spin-driven jet feedback in idealised simulations of galaxy groups and clusters
• The gravitational field of X-COP galaxy clusters
• Entropy of gas and dark matter in galaxy clusters
• The Local Group Mass in the light of Gaia
• The heart of galaxy clusters: demographics and physical properties of cool-core and non-cool-core halos in the TNG-Cluster simulation
• Stability of Cool Cores During Galaxy Cluster Growth: A Joint $Chandra$/SPT Analysis of 67 Galaxy Clusters Along a Common Evolutionary Track Spanning 9 Gyr
• A complete view of the outskirts of the Coma cluster
• Cool Core Bias in Sunyaev-Zel'dovich Galaxy Cluster Surveys
• Connecting turbulent velocities and magnetic fields in galaxy cluster simulations with active galactic nuclei jets
• EAGLE-like simulation models do not solve the entropy core problem in groups and clusters of galaxies
• The SRG/eROSITA All-Sky Survey: Constraints on AGN Feedback in Galaxy Groups
• Rhapsody-C simulations -- Anisotropic thermal conduction, black hole physics, and the robustness of massive galaxy cluster scaling relations
• The hot gas mass fraction in halos. From Milky Way-like groups to massive clusters
• Nature and Nurture in Dark Matter Halos
• Scaling relations of X-ray Luminous Clusters in the Hyper Suprime-Cam Subaru Strategic Program Field
• How the cool-core population transitions from galaxy groups to massive clusters: A comparison of the largest Magneticum simulation with eROSITA, XMM-Newton, Chandra and LOFAR observations
• FLAMINGO: combining kinetic SZ effect and galaxy-galaxy lensing measurements to gauge the impact of feedback on large-scale structure
• The XMAGNET exascale MHD simulations of SMBH feedback in galaxy groups and clusters: Overview and preliminary cluster results