This Chandra image of the afterglow of a gamma-ray burst, known as GRB010222, provides evidence that these massive explosions take place where stars are born. Our team found evidence that the blast wave caused by the fireball brakes against a wall of very dense gas, which we believe is the crowded region where stars form.
Several theories exist about what causes gamma-ray bursts.
Among more popular theories are that gamma-ray bursts come from various combinations of merging neutron stars and black holes, or, from the explosion of massive stars, called hypernovae. We can only gather circumstantial evidence as to where and how they form. Piro's observations support the hypernova model. Scientists believe that within dense star-forming regions, the massive star required for a hypernova explosion evolves extremely rapidly. On astronomical time scales, the supermassive star would evolve over the course of only about one million years.