AGN Feedback Compared: Jets versus Radiation

TL;DR

This study compares the effects of AGN feedback via radiation and jets on galaxy evolution, showing that jets drive stronger outflows while radiation heats gas, with inclined jets interacting more efficiently with the galactic disc.

Contribution

It provides a detailed simulation-based comparison of radiation and jet feedback mechanisms, highlighting their different impacts on the interstellar medium and star formation.

Findings

Jets produce more powerful outflows with stronger mass and momentum transfer.

Radiation heats and rarifies the gas, affecting the cold ISM.

Inclined jets remove the densest gas more efficiently.

Abstract

Feedback by Active Galactic Nuclei is often divided into quasar and radio mode, powered by radiation or radio jets, respectively. Both are fundamental in galaxy evolution, especially in late-type galaxies, as shown by cosmological simulations and observations of jet-ISM interactions in these systems. We compare AGN feedback by radiation and by collimated jets through a suite of simulations, in which a central AGN interacts with a clumpy, fractal galactic disc. We test AGN of $10^{43}$ and $10^{46}$ erg/s, considering jets perpendicular or parallel to the disc. Mechanical jets drive the more powerful outflows, exhibiting stronger mass and momentum coupling with the dense gas, while radiation heats and rarifies the gas more. Radiation and perpendicular jets evolve to be quite similar in outflow properties and effect on the cold ISM, while inclined jets interact more efficiently with all the disc gas, removing the densest $20\%$ in $20$ Myr, and thereby reducing the amount of cold gas available for star formation. All simulations show small-scale inflows of $0.01-0.1$ M$_\odot$/yr, which can easily reach down to the Bondi radius of the central supermassive black hole (especially for radiation and perpendicular jets), implying that AGN modulate their own duty cycle in a feedback/feeding cycle.