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gamma-ray bursts

Spheres representing black holes, with small ones on top, large ones on the bottom, and one midsize example in the middle.

Long-Missing Midsize Black Hole Flashes Into View

March 29, 2021

Black holes seemed to come only in sizes small and XXL. A new search strategy has uncovered a black hole of “intermediate” mass, raising hopes of more to come.


After Black Holes Collide, a Puzzling Flash

March 2, 2016

A satellite spotted a burst of light just as gravitational waves rolled in from the collision of two black holes. Was the flash a cosmic coincidence, or do astrophysicists need to rethink what black holes can do?