Gamma-ray bursts

Astronomers thought they had solved the mystery of gamma-ray bursts. A few recent events suggest otherwise.

There appear to be too many gamma rays coming from the sun. New higher-energy measurements reveal that this excess continues for a bit, then disappears — a cutoff that could help clarify what’s going on.

A recent gamma-ray burst known as the BOAT — “brightest of all time” — appears to have produced a high-energy particle that shouldn’t exist. For some, dark matter provides the explanation.

These ultrabright flashes have recently been tracked for days, upending ideas about the cataclysms that create them.

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.

Astronomers have for the first time matched a gravitational-wave signal to a kilonova’s burst of light, observations that will “go down in the history of astronomy.”

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?