Feedback between Sgr A and B : AGN-Starburst Connection in the Galactic Centre

TL;DR

This paper models how magneto-hydrodynamic waves in the Galactic Centre create a feedback loop between the supermassive black hole Sgr A and star-forming region Sgr B, potentially triggering activity and starburst events.

Contribution

It introduces a novel wave focusing mechanism explaining the AGN-starburst connection without relying on large-scale gas flows.

Findings

MHD waves focus between Sgr A and Sgr B, enabling feedback.

Wave focusing efficiently triggers star formation and AGN activity.

The mechanism addresses angular momentum issues in AGN fueling.

Abstract

Propagation of fast-mode magneto-hydrodynamic (MHD) compression waves is traced in the Galactic Centre. MHD waves produced by the active Galactic nucleus (Sgr A) focus on the molecular clouds such as Sgr B in the central molecular zone, which will trigger star formation, or possibly starburst. MHD waves newly excited by the starburst propagate backward, and focus on the nucleus (Sgr A), where implosive waves compress the nuclear gas to promote fueling the nucleus and may trigger nucleus activity. Echoing focusing of MHD waves between Sgr A (active galactic nucleus: AGN) and Sgr B (starburst) trigger each other at high efficiency by minimal energy requirement. It also solves the problem of angular momentum for AGN fueling, as the focusing waves do not require global gas flow.