Astronomers observe record-breaking gamma-ray burst

Gamma-ray bursts are intense flashes of energetic light produced by catastrophic cosmic events that usually last between a few seconds to a few minutes. Typically, such bursts are formed by the collapse of a massive star into a black hole after it runs out of nuclear fuel, or a collision between a pair of neutron stars. An international team of astronomers have observed a gamma-ray burst designated as GRB 250702B that has broken all records by lasting nearly seven hours. The sustained gamma-ray burst does not fit into any known models for cosmic explosions, but scientists have a few ideas on what could have caused it. 

The gamma-ray burst originated from a distant, dusty galaxy that obscures visible light, with only infrared and high-energy emissions passing through. The data suggests that a narrow jet of material traveling at nearly the speed of light was aimed straight at the Earth, penetrating the thick layers of obscuring dust in the host galaxy. Scientists believe that the gamma-ray burst could have been caused by the death of a massive star, the collision of a star made almost entirely of helium as against hydrogen, or a star being ripped apart after venturing too close to a black hole, resulting in a tidal disruption event. 

The leading explanation is that a black hole consumed a star, but there are uncertainties in how exactly this happened. A black hole containing a few thousand times the mass of the Sun may have shredded a star that passed close to it, or a much smaller black hole may have merged and consumed a stellar companion in a binary system. Gamma-ray bursts were first discovered in 1973, with about 15,000 GRBs being observed since, but  GRB 250702B is in a league of its own because the burst lasted for over twice the duration of the previous longest-known bursts. A paper describing the research has been published in The Astrophysical Journal Letters.