What's in a Fermi Bubble: a quasar episode in the Galactic centre

TL;DR

This paper models a past quasar episode in the Galactic center to explain the origin of the Fermi bubbles, linking SMBH activity with observed gamma-ray lobes and star formation events.

Contribution

It introduces a novel simulation of SMBH feedback that reproduces the Fermi bubble morphology and energetics, supporting a quasar episode in the Milky Way's history.

Findings

Simulation successfully reproduces bubble morphology and energetics

Supports the hypothesis of a past SMBH activity event

Links star formation and SMBH feedback in the Galactic center

Abstract

Fermi bubbles, the recently observed giant (~10 kpc high) gamma-ray emitting lobes on either side of our Galaxy (Su et al. 2010), appear morphologically connected to the Galactic center, and thus offer a chance to test several models of supermassive black hole (SMBH) evolution, feedback and relation with their host galaxies. We use a physical feedback model (King 2003, 2010) and novel numerical techniques (Nayakshin et al. 2009) to simulate a short burst of activity in Sgr A*, the central SMBH of the Milky Way, ~6 Myr ago, temporally coincident with a star formation event in the central parsec. We are able to reproduce the bubble morphology and energetics both analytically (Zubovas et al. 2011) and numerically (Zubovas & Nayakshin, in prep). These results provide strong support to the model, which was also used to simulate more extreme environments (Nayakshin & Power 2010).