Gamma-ray bubbles in Milky Way suggest black hole activity

Nature : Black holes, which feed on stars and gas clouds, can create bright jets that are visible across vast distances. Despite its apparent lack of activity, supermassive black hole Sagittarius A*, thought to be at the center of the Milky Way galaxy, may have been active as recently as 50 000 years ago, according to two researchers studying data from NASA’s Fermi Gamma-Ray Space Telescope. Douglas Finkbeiner and Meng Su of the Harvard–Smithsonian Center for Astrophysics in Cambridge, Massachusetts, report that they have detected evidence of a pair of gamma-ray bubbles emanating from the center of the Milky Way. Although there are several possible sources for the bubbles, Finkbeiner says he believes they are evidence of jets of material expelled by the black hole.