Compact Gamma-Ray Binaries

Abstract: In the recent years a new window on the universe has been opened by ground based and space telescopes that survey the sky by detecting high energy photons, which have energies from a few, up to hundreds of gig electron volts (GeV). Because of the poor angular resolution of the gamma-ray telescopes relative to that of telescopes for longer wavelengths, the ultimate nature of a large fraction of the thousands of sources of gamma-rays observed so far remains unknown. Compact astrophysical objects are among those high energy sources, and recently were discovered in the Milky Way sources that belong to a particular class called “Compact Gamma-Ray Binaries”. They are neutron stars or black holes orbiting around massive stars1,2. The challenges are: 1) to identify the gamma-ray source with a source observed at other wavelengths, 2) determine the properties of the binary system, and 3) understand the physical mechanisms by which gamma-rays are produced. In the Milky Way have been unambiguously identified only a handful of compact binaries radiating at gamma-rays (Cygnus X-3; Cygnus X-1; PSR B1259-63; LSI +61 ° 303; LS 5039; HESS J0632+057; 1FG