# Unifying the micro and macro properties of AGN feeding and feedback

**Authors:** M. Gaspari, A. Sadowski

arXiv: 1701.07030 · 2017-03-22

## TL;DR

This paper presents a unified model linking the micro and macro processes of AGN feeding and feedback, demonstrating consistency with observations and providing a framework for simulations and analysis.

## Contribution

It introduces a first-principles-based unified model connecting SMBH accretion physics with galaxy-scale outflows, integrating relativistic effects and cold accretion processes.

## Key findings

- The model matches observed UFOs and macro outflows across scales.
- Outflows have velocities of a few 10^3 km/s at kpc scales.
- Mass outflow rates are consistent with observations.

## Abstract

We unify the feeding and feedback of supermassive black holes with the global properties of galaxies, groups, and clusters, by linking for the first time the physical mechanical efficiency at the horizon and Mpc scale. The macro hot halo is tightly constrained by the absence of overheating and overcooling as probed by X-ray data and hydrodynamic simulations ($\varepsilon_{\rm BH} \simeq$ 10$^{-3}\, T_{\rm x,7.4}$). The micro flow is shaped by general relativistic effects tracked by state-of-the-art GR-RMHD simulations ($\varepsilon_\bullet \simeq$ 0.03). The SMBH properties are tied to the X-ray halo temperature $T_{\rm x}$, or related cosmic scaling relation (as $L_{\rm x}$). The model is minimally based on first principles, as conservation of energy and mass recycling. The inflow occurs via chaotic cold accretion (CCA), the rain of cold clouds condensing out of the quenched cooling flow and recurrently funneled via inelastic collisions. Within 100s gravitational radii, the accretion energy is transformed into ultrafast 10$^4$ km s$^{-1}$ outflows (UFOs) ejecting most of the inflowing mass. At larger radii the energy-driven outflow entrains progressively more mass: at roughly kpc scale, the velocities of the hot/warm/cold outflows are a few 10$^3$, 1000, 500 km s$^{-1}$, with median mass rates ~10, 100, several 100 M$_\odot$ yr$^{-1}$, respectively. The unified CCA model is consistent with the observations of nuclear UFOs, and ionized, neutral, and molecular macro outflows. We provide step-by-step implementation for subgrid simulations, (semi)analytic works, or observational interpretations which require self-regulated AGN feedback at coarse scales, avoiding the a-posteriori fine-tuning of efficiencies.

## Full text

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## Figures

2 figures with captions in the complete paper: https://tomesphere.com/paper/1701.07030/full.md

## References

76 references — full list in the complete paper: https://tomesphere.com/paper/1701.07030/full.md

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Source: https://tomesphere.com/paper/1701.07030