AGN-driven quenching of star formation: morphological and dynamical implications for early-type galaxies

TL;DR

This study uses hydrodynamical simulations to show that AGN feedback plays a crucial role in transforming star-forming disc galaxies into quiescent elliptical galaxies, aligning with observed galaxy scaling laws.

Contribution

First simulation-based analysis demonstrating how AGN jets quench star formation and induce morphological and dynamical changes in early-type galaxies.

Findings

AGN feedback transforms blue, compact galaxies into red, extended ellipticals.

Simulations with AGN feedback match observed galaxy scaling relations.

AGN jets increase galaxy sizes and stellar velocity dispersion over time.

Abstract

In order to understand the physical mechanisms at work during the formation of massive early-type galaxies, we performed six zoomed hydrodynamical cosmological simulations of halos in the mass range 4.3 10^12 < M_vir < 8.0 10^13 M_sun at z=0, using the Adaptive Mesh Refinement code RAMSES. These simulations explore the role of Active Galactic Nuclei (AGN), through jets powered by the accretion onto supermassive black holes on the formation of massive elliptical galaxies. In the absence of AGN feedback, large amounts of stars accumulate in the central galaxies to form overly massive, blue, compact and rotation-dominated galaxies. Powerful AGN jets transform the central galaxies into red extended and dispersion-dominated galaxies. This morphological transformation of disc galaxies into elliptical galaxies is driven by the efficient quenching of the in situ star formation due to AGN feedback, which transform these galaxies into systems built up by accretion. For galaxies mainly formed by accretion, the proportion of stars deposited farther away from the centre increases, and galaxies have larger sizes. The accretion is also directly responsible for randomising the stellar orbits, increasing the amount of dispersion over rotation of stars as a function of time. Finally, we find that our galaxies simulated with AGN feedback better match the observed scaling laws, such as the size-mass, velocity dispersion-mass, fundamental plane relations, and slope of the total density profiles at z~0, from dynamical and strong lensing constraints.