Radiative and Momentum Based Mechanical AGN Feedback in a 3-Dimensional Galaxy Evolution Code

TL;DR

This paper introduces a 3D galaxy evolution simulation incorporating new mechanical and radiative AGN feedback models, revealing higher wind velocities and energy emissions compared to traditional thermal feedback, with implications for black hole growth and galaxy dynamics.

Contribution

The study develops and tests a novel 3D simulation framework with momentum-based mechanical feedback and X-ray radiation effects, improving realism in AGN feedback modeling.

Findings

Higher wind velocities (~1000-3000 km/s) compared to thermal models.

Mechanical feedback emits over 30% of BH energy in winds.

Fluctuations in radiative and wind outputs are significantly larger.

Abstract

We study the growth of black holes (BHs) in galaxies using three-dimensional smoothed particle hydrodynamic simulations with new implementations of the momentum mechanical feedback, and restriction of accreted elements to those that are gravitationally bound to the BH. We also include the feedback from the X-ray radiation emitted by the BH, which heats the surrounding gas in the host galaxies, and adds radial momentum to the fluid. We perform simulations of isolated galaxies and merging galaxies and test various feedback models with the new treatment of the Bondi radius criterion. We find that overall the BH growth is similar to what has been obtained by earlier workers using the Springel, Di Matteo, & Hernquist algorithms. However, the outflowing wind velocities and mechanical energy emitted by winds are considerably higher (v_w ~ 1000-3000 km/s) compared to the standard thermal feedback model (v_w ~ 50-100 km/s). While the thermal feedback model emits only 0.1 % of BH released energy in winds, the momentum feedback model emits more than 30 % of the total energy released by the BH in winds. In the momentum feedback model, the degree of fluctuation in both radiant and wind output is considerably larger than in the standard treatments. We check that the new model of the BH mass accretion agrees with analytic results for the standard Bondi problem.