[NCTS Physics Research Highlights] Hsiang-Yi Karen Yang 'Fermi and eRosita bubbles as relics of the past activity of the Galaxy’s central black hole', Nature Astronomy (2022)
Fermi and eRosita bubbles as relics of the past activity of the Galaxy’s central black hole
Yang, HY.K., Ruszkowski, M. & Zweibel, E.G.
Nature Astronomy 6, 584–591 (2022)
The newly launched X-ray satellite, eRosita, has recently revealed two gigantic bubbles extending to ~80 degrees above and below the Galactic center. The morphology of these “eRosita bubbles” bears a remarkable resemblance to the Fermi bubbles previously discovered in gamma rays. The physical origin of these striking structures has been intensely debated. We propose a theoretical model in which the eRosita and Fermi bubbles could be simultaneously explained by a single event of jet activity from the central supermassive black hole a few million years ago. Using numerical simulations, we show that this model could successfully reproduce the morphology and multi-wavelength spectra of the observed bubbles, which allows us to derive critical constraints on the energetics and timescales of the outburst. This study serves as an important step forward in our understanding of the past Galactic center activity of our Milky Way Galaxy, and may bring valuable insights into the broader picture of supermassive black hole-galaxy co-evolution in the context of galaxy formation.