Active Galactic Nucleus Feedback in an Elliptical Galaxy. IV. The Importance of the Jet Wind Coupling
Minhang Guo, Feng Yuan, Suoqing Ji, Bocheng Zhu
TLDR
This paper shows that nonlinear coupling between AGN jets and winds is crucial for efficient feedback and star formation suppression in elliptical galaxies.
Key contributions
- Introduces jet feedback into the MACER framework for elliptical galaxy evolution.
- Compares JetOnly, WindOnly, and FullFeedback models for star formation rates.
- Shows nonlinear jet-wind coupling in FullFeedback strongly suppresses star formation.
- Highlights Kelvin-Helmholtz instability's role in efficient energy dissipation.
Why it matters
This research significantly advances our understanding of active galactic nucleus (AGN) feedback mechanisms. By demonstrating the critical role of nonlinear jet-wind coupling, it provides new insights into how AGNs regulate star formation and influence the evolution of elliptical galaxies. This is crucial for accurate galaxy evolution models.
Original Abstract
This is the fourth paper of our series investigating the effects of active galactic nucleus (AGN) feedback in the evolution of an elliptical galaxy using the {\it MACER} framework. While previous works considered only AGN radiation and wind, we now add jet feedback. The values of the jet parameters are taken from small-scale general relativity MHD simulations of black hole accretion. We run three models: {\tt FullFeedback}, {\tt JetOnly}, and {\tt WindOnly}. Time-averaged star formation rates are $10^{-1}$, $10^{-2}$, and $10^{-3} \mathrm{M}_\odot\,\mathrm{yr}^{-1}$ in {\tt JetOnly}, {\tt WindOnly}, and {\tt FullFeedback}, respectively. Despite the higher jet power, jet feedback is less efficient than wind due to a small opening angle and low momentum flux. The much lower star formation rate in {\tt FullFeedback} indicates nonlinear coupling between jet and wind, with stronger suppression than the linear sum. The AGN energy dissipation efficiency values (fraction of injected kinetic energy dissipated via turbulence and shock) are 0.64 ({\tt FullFeedback}), 0.48 ({\tt WindOnly}), and 0.26 ({\tt JetOnly}). In the {\tt FullFeedback} model the wind-jet shear results in Kelvin-Helmholtz instability, driving stronger turbulence that effectively converts AGN kinetic energy into heating.
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