In June 2020, astronomers, using the Zwicky Transient Facility (ZTF) located at Palomar Observatory in California, reported observational details, loosely associated with the GW190521g trigger, of the merging of two black holes, within the vicinity of a very large third black hole, that uncharacteristically emitted a flash of light. If true, the event is claimed to be the first ever light flare observed in the merger of two black holes by astronomers.[1][3][3][15] Mergers of black holes do not typically emit any light whatsoever.