AGN feedback and triggering of star formation in galaxies

TL;DR

This paper investigates how AGN feedback can trigger star formation in host galaxies by analyzing gas dynamics and dark matter profiles, suggesting a mechanism for inside-out galaxy growth.

Contribution

It introduces a model where AGN-driven gas shells can induce star formation, linking feedback processes to galaxy evolution patterns.

Findings

AGN feedback can trigger star formation in the galactic shell.

Different dark matter profiles affect gas escape conditions.

Star formation occurs at larger radii over time, supporting inside-out growth.

Abstract

Feedback from the central black hole in active galactic nuclei (AGN) may be responsible for establishing the observed MBH-sigma relation and limiting the bulge stellar mass of the host galaxy. Here we explore the possibility of AGN feedback triggering star formation in the host galaxy. We consider a shell of dusty gas, driven outwards by radiation pressure, and analyse its escape/trapping condition in the galactic halo for different underlying dark matter potentials. In the isothermal potential, we obtain that the standard condition setting the observed MBH-sigma relation is not sufficient to clear gas out of the entire galaxy; whereas the same condition is formally sufficient in the case of the Hernquist and Navarro-Frenk-White profiles. The squeezing and compression of the inhomogeneous interstellar medium during the ejection process can trigger star formation within the feedback-driven shell. We estimate the resulting star formation rate and total additional stellar mass. In this picture, new stars are formed at increasingly larger radii and successively populate the outer regions of the host galaxy. This characteristic pattern may be compared with the observed 'inside-out' growth of massive galaxies.