Atmospheric Circulation in Simulations of the AGN-CGM Connection at Halo Masses $\sim 10^{13.5}, M_\odot$

TL;DR

This study uses numerical simulations to explore how kinetic AGN feedback influences the circumgalactic medium, revealing large-scale circulation's role in regulating galaxy atmospheres and the importance of feedback parameters.

Contribution

It demonstrates the impact of kinetic AGN feedback on CGM circulation and how feedback parameters like jet opening angle affect galaxy atmosphere regulation.

Findings

Large-scale CGM circulation reconfigures galactic atmospheres.

Most AGN energy lifts CGM gas rather than heats the galaxy.

Feedback parameters significantly influence AGN-CGM coupling.

Abstract

Coupling between active galactic nuclei (AGN) and the circumgalactic medium (CGM) is critical to the interplay between radiative cooling and feedback heating in the atmospheres of the universe's most massive galaxies. This paper presents a detailed analysis of numerical simulations showing how kinetic AGN feedback with a strong momentum flux interacts with the CGM. Our analysis shows that large scale CGM circulation plays an important role in reconfiguring the galactic atmosphere and regulating the atmosphere's central entropy level. We find that most of the AGN energy output goes into lifting of circumgalactic gas rather than heating of atmospheric gas within the galaxy, consequently reconfiguring the circumgalactic medium (CGM) in our simulations. Large scale (10s of kpc) circulation of the CGM on ~ 10-100 kpc scales therefore plays a critical role in preventing over-cooling of gas in these simulated galaxies. The simulations also show that our choices of accretion efficiency and jet opening angle significantly affect the AGN-CGM coupling. Reducing the jet opening angle to quarter of the fiducial opening angle increases the jet momentum flux, enabling it to drill through to larger radii without effectively coupling with the CGM at the center ( $r < 5$ kpc). Outflows with a lower momentum flux decelerate and thermalize the bulk of their energy at smaller radii ($r \lesssim 10$ ).