The Fermi Bubbles and the Galactic Center

Two giant lobes of gamma-ray emitting plasma, known as the Fermi Bubbles, extend 12 kpc above and below the Galactic Center. They are thought to be created by a past episode of AGN activity at the Galactic Center. Our team has led two approved HST programs (in Cycles 21 and 25) to study the Bubbles in ultraviolet absorption using COS and STIS. This dataset has opened a new UV window on the Galactic Center and allowed us to study the kinematics, spatial extent, chemical abundances, and physical conditions of the nuclear outflow. Our ongoing work is studying stellar sightlines near the Galactic Center, and probing the ionization conditions in the flow.