Binary Revelation

摘要

Binary star systems that contain a neutron star or a black hole are expected to emit gamma rays. These gamma-ray binaries are a rare class of objects, which are also expected to emit x-rays. Indeed, several such systems were initially detected through their x-ray emission. The Fermi LAT Collaboration (p. 189; see the Perspective by Mirabel) reports the detection of a gamma-ray binary that was previously unknown as an x-ray source.