Active Galactic Nucleus Feedback in an Elliptical Galaxy. IV. The Importance of the Jet Wind Coupling

TL;DR

This study investigates the combined effects of jet and wind feedback from active galactic nuclei on elliptical galaxy evolution, revealing nonlinear coupling and enhanced turbulence-driven heating.

Contribution

It introduces a model incorporating both jet and wind feedback, demonstrating their nonlinear interaction and impact on star formation suppression.

Findings

Jet feedback alone is less efficient than wind feedback in suppressing star formation.

Nonlinear coupling between jet and wind enhances feedback effectiveness.

Turbulence from shear instabilities converts kinetic energy into heat more effectively.

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.