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