Gamma rays from a dwarf galaxy solve an astronomical mystery

A glowing bubble known as a “cocoon,” which appears to be inside one of the massive gamma-ray emission from the center of our galaxy dubbed “Fermi bubbles,” has baffled astronomers since its discovery in 2012.

in new search Publishing in Nature Astronomy, we show that the cocoon is caused by gamma rays emitted from rapidly rotating extreme stars called “millisecond pulsars” found in the Sagittarius dwarf galaxy, which orbits the Milky Way. While our results clarify the mystery of the cocoon, they overshadow attempts to search for dark matter in any gamma-ray glow it might emit.