Role of AGN and star formation feedback in the evolution of galaxy outflows

ABSTRACT We conducted 3D-magnetohydrodynamic simulations to investigate the feedback processes in the central 1-kpc scale of galaxies hosting both active star formation (SF) and an active galactic nucleus (AGN) wind. Our simulations naturally generated a turbulent and clumpy interstellar medium driven by SF evolution. We found that the AGN-wind duty cycle plays a crucial role in shaping the evolution of the outflows. A single duty cycle (which can repeat several times over the galaxy lifetime) consists of an active, a remnant and an inactive phase, lasting up to 1.5 Myr in our simulations. The duration of the cycle increases with larger star formation rate (SFR) and smaller AGN-wind power (tested for luminosities 1042–1044 erg s−1 and SFR = 1–1000 M⊙ yr−1). The feedback on SF, whether positive or negative, depends on various factors, including the AGN outflow opening angle, power, and phase of activity, as well as the initial SFR. The passage of the AGN wind enhances SF in a ring around it, resembling the structures observed in ULIRGs (Ultraluminous Infrared Galaxies) and LINERS (low-ionization nuclear emission-line region), and is stronger for larger AGN power or SFR. Also, a higher SFR enhances the mixing of interstellar matter with the AGN wind, resulting in a greater number of colder, denser structures with volume filling factors ∼0.02 to 0.12 and velocities comparable to those observed in Seyferts and LINERs, but smaller than those observed in ULIRGs. The efficiency of the AGN wind in transporting mass to kiloparsec distances diminishes with increasing SFR. The mass-loss rates range from 50 to 250 M⊙ yr−1 within the initial 2 Myr of evolution, which aligns with observed rates in nearby Seyferts and ULIRGs.