Piro and collaborators observed the afterglow emission that follows GRBs and found evidence that the blast wave was braking against very dense gas, such as would be found in regions where new stars were forming. The results support the hypernova model of GRBs, in which the explosion of an extremely massive star produces an enormous blast of material. This fireball expands at relativistic speeds. Meanwhile, astronomers using the Parkes radiotelescope in Australia have found 30 young pulsars, counterparts of otherwise unidentified galactic gamma-ray sources. Previously, seven gamma-ray sources had been identified with pulsars.
Pulsars are neutron stars formed by the collapse of massive stars during supernova explosions.
Their intense magnetic fields are expected to make them prolific sources of high-energy radiation. Article 8 of 15.