X-ray bubbles in the circumgalactic medium of TNG50 Milky Way- and M31-like galaxies: signposts of supermassive black hole activity

The TNG50 cosmological simulation produces X-ray emitting bubbles, shells, and cavities in the circumgalactic gas above below stellar disks of Milky Way- Andromeda-like galaxies with morphological features reminiscent eROSITA Fermi bubbles Galaxy. Two-thirds 198 MW/M31 analogues inspected at z=0 show one or more large-scale, coherent over-pressurized that impinge into gaseous halo. Some include a succession shells increasing size, ranging from few to many tens kpc. These are prominent pressure, emission temperature, often exhibit sharp boundaries typical shock Mach numbers 2-4. outflows maximum (95th pctl) radial velocities 100-1500 km/s. expand speeds as high 1000-2000 km/s (about 1-2 kpc/Myr), but great diversity larger expanding slower speeds. bubble is 10^6.4-7.2 K temperatures enriched metallicities 0.5-2 solar. In TNG50, manifestation episodic, kinetic, wind-like energy injections supermassive black holes galaxy centers accrete low Eddington ratios. According X-ray, possibly gamma-ray, similar those observed Way should be frequent feature disk-like prior to, on verge of, being quenched. They within grasp local Universe.