Fermi/eROSITA bubbles: Repeated collimated outbursts from the Galactic Center

The Fermi (FBs) and ROSAT/eROSITA (RBs) bubbles are giant, multi-wavelength structures that emanate from our Galactic center. I will show that each bubble terminates at a forward shock driven by a collimated outflow, and will present an analytic model that describes the bubble evolution and relates its outflow properties to observable parameters. In a simple scenario where both FBs and RBs originate from identically parametrized but temporally separated outbursts, 2D-axisymmetric hydrodynamic simulations successfully model both structures in a self-consistent manner. Constraints on age, outburst energy, and Mach number will be presented for each bubble.