On the Hydrodynamic Interplay Between a Young Nuclear Starburst and a Central Super Massive Black Hole

TL;DR

This study uses 1D simulations to explore how young nuclear starbursts and central supermassive black holes interact hydrodynamically, revealing a bimodal flow with implications for black hole accretion and star formation.

Contribution

It extends previous semi-analytic models to more powerful starbursts, demonstrating a bimodal hydrodynamic solution including accretion and wind regimes.

Findings

Bimodal hydrodynamic solution confirmed in all cases.

Larger starbursts lead to increased SMBH accretion rates.

Powerful winds can inhibit interstellar matter from reaching the starburst.

Abstract

We present 1D numerical simulations, which consider the effects of radiative cooling and gravity on the hydrodynamics of the matter reinserted by stellar winds and supernovae within young nuclear starbursts with a central supermassive black hole (SMBH). The simulations confirm our previous semi-analytic results for low energetic starbursts, evolving in a quasi-adiabatic regime, and extend them to more powerful starbursts evolving in the catastrophic cooling regime. The simulations show a bimodal hydrodynamic solution in all cases. They present a quasi-stationary accretion flow onto the black hole, defined by the matter reinserted by massive stars within the stagnation volume and a stationary starburst wind, driven by the high thermal pressure acquired in the region between the stagnation and the starburst radii. In the catastrophic cooling regime, the stagnation radius rapidly approaches the surface of the starburst region, as one considers more massive starbursts. This leads to larger accretion rates onto the SMBH and concurrently to powerful winds able to inhibit interstellar matter from approaching the nuclear starburst. Our self-consistent model thus establishes a direct physical link between the SMBH accretion rate and the nuclear star formation activity of the host galaxy and provides a good upper limit to the accretion rate onto the central black hole.