It would take another two decades and contributions from the Italian Space Agency's BeppoSax and NASA's Compton Gamma-Ray Observatory to show that these outbursts occur far beyond our Milky Way ...

"This is the region where the detector on NASA's orbiting Compton Gamma Ray Observatory makes observations. "Just why Markarian 421 radiates in this unusual manner is a question scientists are very ...

in 1992 at the Smithsonian's Whipple Observatory in southern Arizona. This source had been detected earlier by NASA's Compton Gamma Ray Observatory. The gamma-ray telescopes on the Compton Observatory ...