Introducing RAFIKI: Refining AGN Feedback in Kinetic Implementations

TL;DR

RAFIKI introduces a new suite of cosmological simulations that vary AGN wind mass loading to better understand feedback processes affecting galaxy evolution, black hole growth, and the circumgalactic medium.

Contribution

It presents RAFIKI, a novel simulation framework that separates kinetic feedback modes, enabling detailed analysis of AGN feedback effects on galaxies and black holes.

Findings

Lower-velocity quasar mode cannot quench massive galaxies.

Quasar mode influences black hole growth and star formation in intermediate-mass galaxies.

Degeneracies in feedback parameters limit current constraints on AGN feedback.

Abstract

Modern cosmological simulations have now matured to the point of reproducing the evolution of realistic galaxy populations across cosmic time. These simulations rely on feedback from active galactic nuclei (AGN) to quench massive galaxies, yet the details of this process remain poorly understood. To address this issue, we introduce RAFIKI (Refining AGN Feedback In Kinetic Implementations), a novel suite of simulations built upon SIMBA-C that vary the mass loading of AGN-driven winds. Unlike the fiducial SIMBA-C simulation, RAFIKI separates the efficiencies of the two kinetic feedback modes, enabling a detailed study of their impact on galaxies, black holes, and the circumgalactic medium. We explore a range of galaxy and baryon properties in the RAFIKI runs and find that even with enhanced mass loading, the lower-velocity, quasar-type mode cannot quench massive galaxies. However, it plays a significant role in regulating black hole growth and star formation in intermediate-mass galaxies. We also uncover degeneracies in the parameter space that highlight the limited current constraints on AGN feedback. RAFIKI provides a controlled framework to disentangle these degeneracies using current and upcoming observations.