Nathaniel Butler / ASU
When stars die and collapse to form black holes, a powerful explosion — second only to the Big Bang itself — occurs. These gamma-ray bursts take place billions of light years away. Across space and therefore time, they're a window into the early universe that opens for just a few milliseconds to a minute. By the time a telescope is turned, they're typically gone.
Last year though, researchers were able to observe an unusually bright one — GRB 160625B, pictured above— using six telescopes on the ground and in space. They caught it early to enough to measure strong changes in the polarized light of the burst for the first time. "That, in turn, tells us that the release of magnetic energy is an important ingredient in these exotic explosions," says Arizona State University's Nathaniel Butler.
A new picture: Spiraling electrons cause radiation that powers magnetic jets in the first moments of the explosion. The magnetic fields then break down and are largely replaced by matter from the dying star that falls into the black hole and is ejected again. Researchers have known about these two processes but thought only one was responsible. Now, it seems it could be both.