Rapidly alerting the astronomical community is key for following up many of the events found. For about one hundred transients nothing out of the ordinary was observed by Gaia during the months before and after detection, indicating that the event leading to the enhanced emission of light was short.

"Such events have great value because they could allow astronomers to study for a brief period previously invisible supermassive black holes", says Jonker. "Especially the short-duration events could point us to the location of the so far elusive intermediate-mass black holes ripping stars apart."

The leading explanation for most events is that supermassive black holes residing in the nuclei of galaxies suddenly become much more active as the amount of gas falling into the black hole surges and lights up the close environment of the black hole. This fresh fuel may be extracted from a star which is ripped apart by the enormous gravitational pull of the black hole.

Zuzanna Kostrzewa-Rutkowska and Peter Jonker have recently started a dense campaign to decipher the nature of the 480 new transients using the William Herschel Telescope.