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arxiv: 2511.02796 · v4 · pith:GFPQMEXPnew · submitted 2025-11-04 · 🌌 astro-ph.GA

Solving the cooling flow problem with combined jet-wind AGN feedback

Aoyun He , Feng Yuan , Suoqing Ji , Minhang Guo , Yuan Li , Haiguang Xu , Ming Sun , Haojie Xia
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Yuanyuan Zhao
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Pith reviewed 2026-05-18 00:56 UTC · model grok-4.3

classification 🌌 astro-ph.GA
keywords AGN feedbackcooling flow problemgalaxy clustersjet-wind shearturbulence heatinghydrodynamic simulationPerseus clusterblack hole accretion
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The pith

Combined jet and wind feedback from AGN solves the cooling flow problem in galaxy clusters.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper shows that a hydrodynamic simulation of a relaxed galaxy cluster like Perseus succeeds when both jets and winds are included with properties taken from GRMHD accretion models and observations. Jet-only and wind-only runs fail to match the observed cold gas mass, star formation rate, thermodynamic profiles, and black hole growth. The interaction between the jet and wind creates shear-driven turbulence that converts kinetic energy into heat far more efficiently, raising heating rates by factors of three to six. This matters because it offers a concrete mechanism that can keep the hot intracluster gas from cooling and collapsing into stars at the high rates expected from simple radiative losses.

Core claim

The authors run an idealized hydrodynamic simulation of a Perseus-like cluster with no merger history using the MACER framework. They inject both jets and winds whose properties are fixed by general relativistic magnetohydrodynamic simulations of black hole accretion and by observations. The combined jet-wind model reproduces the cold gas mass, star formation rate, thermodynamic radial profiles, and black hole growth, while jet-only and wind-only versions do not. Success arises because jet-wind shear drives turbulence that boosts the conversion of kinetic energy to thermal energy, increasing heating efficiency by factors of three and six relative to wind-only and jet-only cases.

What carries the argument

Jet-wind shear that generates turbulence to raise the fraction of feedback energy converted from kinetic to thermal form.

If this is right

  • Both jet and wind components must be modeled together to reproduce multiple cluster observables at once.
  • Shear-driven turbulence supplies the missing heating efficiency that single-mode feedback lacks.
  • Black hole growth remains self-regulated when the combined feedback is active.
  • The same turbulence mechanism can be examined in other hydrodynamic runs that vary jet power or wind speed.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Clusters with recent mergers may need extra terms for ram-pressure stripping or sloshing to keep the same heating balance.
  • X-ray or radio maps that resolve shear layers between jet and wind outflows could directly test the turbulence source.
  • The efficiency gain reported here could be checked by repeating the simulation at higher resolution or with different viscosity prescriptions.

Load-bearing premise

The injected jet and wind properties correctly represent real AGN output and the idealized no-merger relaxed cluster captures the dominant balance of heating and cooling.

What would settle it

If high-resolution observations of a Perseus-like cluster show a cold gas mass or star formation rate that lies well outside the range produced by the combined jet-wind simulation, the central claim would be ruled out.

Figures

Figures reproduced from arXiv: 2511.02796 by Aoyun He, Feng Yuan, Haiguang Xu, Haojie Xia, Ming Sun, Minhang Guo, Suoqing Ji, Yuan Li, Yuanyuan Zhao.

Figure 1
Figure 1. Figure 1: Schematic of the fiducial JetWind model. The dashed circle marks the simulation’s inner boundary, located within the Bondi radius, enabling self-consistent calculation of the black hole accretion rate and accurate coupling of AGN outputs to the intracluster medium (ICM). Jet and wind parameters are taken from GRMHD simulations. Shear between them triggers Kelvin– Helmholtz instabilities that drive turbulen… view at source ↗
Figure 2
Figure 2. Figure 2: Time evolution of key quantities in the three models. Results are shown for the JetWind (solid red), JetOnly (dashed blue), and WindOnly (dashed grey) models. Top: star formation rate (SFR); the black dashed line and grey shaded region mark the SFR of NGC 1275 (the Perseus BCG) and its 68 % confidence interval (30). Second: cold gas mass; the grey band denotes the molecular gas mass observed in Perseus (31… view at source ↗
Figure 3
Figure 3. Figure 3: Radial profiles of the intracluster medium. Density-weighted entropy (top), density (middle), and temperature (bottom) profiles are shown for the three models, color-coded by time. Shaded areas mark the 10th–90th percentiles. Dashed lines and red bands indicate observed profiles from the ACCEPT cluster sample (34) and XMM-Newton data of Perseus (35,36). Only the JetWind model reproduces all observed entrop… view at source ↗
Figure 4
Figure 4. Figure 4: Radial profiles of the cooling-to-free-fall time ratio. Shown are density-weighted 𝑡cool/𝑡ff profiles for the JetOnly (left), JetWind (middle), and WindOnly (right) models. Colored curves indicate simulation times, as shown by the color bar. The gray shaded regions mark observational ranges for cool-core clusters from the ACCEPT database (34), while the black dashed line shows Perseus data (35,36). Only th… view at source ↗
read the original abstract

Active galactic nucleus (AGN) feedback is widely viewed as the most promising solution to the long-standing cooling flow problem in galaxy clusters, yet previous models prescribe jet properties inconsistent with accretion physics. We perform an idealized hydrodynamic simulation of a galaxy cluster with no merger history and a relaxed state, with its other properties similar to the Perseus cluster using the MACER framework, incorporating both jets and winds whose properties are constrained by general relativistic magnetohydrodynamic simulations of black hole accretion and observations. The combined feedback reproduces key observables, including cold gas mass, star formation rate, thermodynamic radial profiles, and black hole growth, while jet-only or wind-only models fail. The success arises from turbulence driven by jet-wind shear that enhances kinetic-to-thermal energy conversion, boosting heating efficiency by factors of three and six relative to wind-only and jet-only cases, respectively.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript presents an idealized hydrodynamic simulation of a relaxed, Perseus-like galaxy cluster using the MACER framework. It incorporates AGN feedback with both jets and winds whose properties are taken from GRMHD accretion simulations and observational constraints rather than tuned to the cluster data. The combined jet-wind model is shown to reproduce cold gas mass, star formation rate, thermodynamic radial profiles, and black hole growth, while jet-only and wind-only runs fail. The authors attribute the difference to shear-driven turbulence between the jet and wind that enhances kinetic-to-thermal energy conversion, yielding heating efficiencies three and six times higher than the wind-only and jet-only cases, respectively.

Significance. If the central result holds, the work offers a concrete demonstration that multi-component AGN feedback can self-regulate cluster cores without direct parameter fitting to observables. The grounding of jet and wind properties in independent GRMHD runs and observations is a clear strength that reduces circularity relative to many earlier models. The reported efficiency gains from shear turbulence, if robust, would be useful for sub-grid prescriptions in cosmological simulations.

major comments (2)
  1. [Initial conditions section] Initial conditions section: The simulation is performed on a static, relaxed initial condition with no merger history. This setup omits sloshing, minor mergers, and large-scale bulk motions that are observed in real Perseus-like systems and that inject additional turbulence and mixing. Because the claimed success of the combined feedback rests on the dominance of jet-wind shear turbulence in this idealized environment, it remains unclear whether the same heating channel would operate at comparable efficiency once external dynamical drivers are included. A controlled test with added velocity perturbations or a more dynamic initial condition is needed to establish that the mechanism solves the cooling-flow problem under realistic conditions.
  2. [Results on energy conversion] Results on energy conversion: The factors of three and six in heating efficiency are load-bearing for the explanation of why the combined model succeeds. The precise definition of heating efficiency (e.g., the ratio of thermal energy deposited within the core to the total kinetic energy injected, the radial range, and the time interval over which it is averaged) should be stated explicitly, ideally with reference to the relevant equation or diagnostic plot. Without this, it is difficult to judge whether the reported boost is robust to reasonable variations in analysis choices.
minor comments (2)
  1. [Figure 4] Figure 4 (or equivalent comparison plot): The time evolution panels would benefit from explicit indication of the time-averaging window and any error bands used for the thermodynamic profiles.
  2. [Notation] Notation: The term 'shear turbulence' is used in the abstract and discussion; ensure it is defined consistently when first introduced in the methods or results.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their thoughtful and constructive comments, which have helped clarify several aspects of our work. We respond to each major comment below.

read point-by-point responses

  1. Referee: [Initial conditions section] Initial conditions section: The simulation is performed on a static, relaxed initial condition with no merger history. This setup omits sloshing, minor mergers, and large-scale bulk motions that are observed in real Perseus-like systems and that inject additional turbulence and mixing. Because the claimed success of the combined feedback rests on the dominance of jet-wind shear turbulence in this idealized environment, it remains unclear whether the same heating channel would operate at comparable efficiency once external dynamical drivers are included. A controlled test with added velocity perturbations or a more dynamic initial condition is needed to establish that the mechanism solves the cooling-flow problem under realistic conditions.

    Authors: We agree that the simulation employs a static, relaxed initial condition with no merger history, as stated in the abstract and Section 2. This idealized setup was chosen specifically to isolate the contribution of jet-wind shear turbulence to the heating efficiency without external dynamical drivers. Our results demonstrate that the combined feedback can self-regulate the core through this internal mechanism alone. We will add an expanded discussion of this limitation in the revised manuscript, including how external turbulence sources might interact with or supplement the shear-driven channel. A full controlled test with dynamic initial conditions lies beyond the scope of the present study, which focuses on a controlled demonstration of the multi-component AGN feedback model. revision: partial

  2. Referee: [Results on energy conversion] Results on energy conversion: The factors of three and six in heating efficiency are load-bearing for the explanation of why the combined model succeeds. The precise definition of heating efficiency (e.g., the ratio of thermal energy deposited within the core to the total kinetic energy injected, the radial range, and the time interval over which it is averaged) should be stated explicitly, ideally with reference to the relevant equation or diagnostic plot. Without this, it is difficult to judge whether the reported boost is robust to reasonable variations in analysis choices.

    Authors: We thank the referee for highlighting the need for greater precision. The heating efficiency is defined as the ratio of the thermal energy increase within the core (r < 100 kpc) to the total kinetic energy injected by the AGN feedback, averaged over the quasi-steady phase from 1.5 to 3 Gyr. This is computed from the diagnostics in Equation (3) and shown in Figure 6. We will revise the text to state this definition explicitly in a dedicated paragraph in Section 3.2, with direct references to the equation and figure, and will briefly discuss sensitivity to reasonable variations in the radial cut and averaging window. revision: yes

Circularity Check

0 steps flagged

No significant circularity; inputs from independent GRMHD and observations

full rationale

The paper's derivation proceeds from an idealized hydrodynamic simulation whose jet and wind properties are set by external GRMHD accretion simulations and observations rather than fitted to the Perseus-like cluster observables. The reported reproduction of cold gas mass, SFR, thermodynamic profiles and BH growth, along with the claimed efficiency boost from jet-wind shear turbulence, emerges as a simulation outcome. No equation or result is shown to reduce by construction to a fitted parameter or self-citation chain; the idealized no-merger setup is an explicit modeling choice whose limitations are separate from circularity.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim rests on external GRMHD constraints for jet and wind properties plus the modeling choice of an idealized relaxed cluster; no new particles or forces are introduced.

axioms (1)
  • domain assumption The simulated cluster has no merger history and is in a relaxed state with properties similar to Perseus
    Stated explicitly in the abstract as the setup chosen to isolate feedback effects.

pith-pipeline@v0.9.0 · 5698 in / 1366 out tokens · 44372 ms · 2026-05-18T00:56:26.294482+00:00 · methodology

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Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. A systematic study of AGN feedback in a disk galaxy using MACER II: predictions of X-ray surface brightness profiles and comparison with eROSITA observations

    astro-ph.GA 2026-03 conditional novelty 5.0

    AGN feedback simulations predict X-ray surface brightness profiles that match eROSITA CGM observations out to 100 kpc.

Reference graph

Works this paper leans on

5 extracted references · 5 canonical work pages · cited by 1 Pith paper · 1 internal anchor

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