eROSITA witnesses the awakening of massive black holes

Using the SRG/eROSITA all-sky survey data, scientists at the Max Planck Institute for Extraterrestrial Physics have found two previously quiescent galaxies that now show quasi-periodic eruptions. The nuclei of these galaxies light up in X-rays every few hours, reaching peak luminosities comparable to that of an entire galaxy. The origin of this pulsating behavior is unclear. A possible cause is a stellar object orbiting the central black hole. As these galaxies are relatively close and small, th...