Researchers at DESY have compiled an extensive catalogue of variable sources of cosmic gamma radiation. For his doctoral thesis, Matteo Giomi, working at DESY in Zeuthen, analysed almost 7.5 years of observational data from NASA’s “Fermi” space telescope. Over that period, the “Large Area Telescope” (LAT) on board the satellite registered a total of 4547 bursts of gamma radiation, known as flares. Thanks to improved analytical methods, Giomi was able to assign these flares to 518 variable sources. The “Fermi All-Sky Variability Analysis” (FAVA) also lists 77 unknown sources, whose identity has not yet been determined. The “Fermi” scientists are presenting their catalogue in the Astrophysical Journal.