Speaker
Description
AGNs flicker in bursts lasting ${\sim}0.1$ Myr, punctuated by quiescent intervals. Despite the low duty cycle, the total energy released exceeds the binding energy of the galactic bulges. This indicates that AGN-released energy couples inefficiently to the surrounding gas, but can still affect the host galaxy, for example via wind-driven outflows. Indeed, fast (${>}500$ km s$^{-1}$) outflows remove the gas from the bulge, quenching star formation. However, the effect of slower outflows is uncertain.
We aim to constrain the effect of slow AGN outflows in galactic centres. Using SPH simulations, we track the propagation of a multiphase outflow created by a single Eddington-limited AGN episode. As it expands through the initially spherical approximately isothermal gas shell, the outflow both enhances star formation in the galactic disc and forms stars itself as it fragments. On the other hand, the long-term effect is negative as the outflow expels large amounts of gas. We will detail the relative importance of negative and positive feedback and their impact on the radial and velocity distributions of the stellar population.
Observations so far have provided only limited evidence of positive AGN feedback, but this should change with upcoming surveys. Our results can be used to reconstruct recent galactic activity from observed AGN-enhanced star formation, or provide insights into the contribution of positive AGN feedback to the scatter of the $M-\sigma$ relation.
