Simulating the Fermi Bubbles as Forward Shocks Driven by AGN Jets

Understand

The Fermi bubbles are two giant bubbles in gamma rays lying above and below the Galactic center (GC).

• Despite numerous studies on the bubbles, their origin and emission mechanism remain elusive.
• Here we use a suite of hydrodynamic simulations to study the scenario where the cosmic rays (CRs) in the bubbles are mainly accelerated at the forward shocks driven by a pair of opposing jets from Sgr A*.
• We find that an active galactic nucleus (AGN) jet event happened $5-6$ Myr ago can naturally reproduce the bilobular morphology of the bubbles, and the postshock gas temperature in the bubbles is heated to $\sim0.4$ keV, consistent with recent X-ray observations.