Accelerate

Astronomers have spotted extremely high-energy gamma rays coming from a pulsar. Pulsars are rapidly rotating neutron stars with strong magnetic fields. Arache Diannati-Atai at Paris Cite University in France and his colleagues have found that one—the Vela pulsar—emits gamma rays with energies of more than 20 teraelectronvolts, about 20 times more than any other known pulsar.

There are two models of how pulsars accelerate the particles of light, or photons, in gamma rays, both involving high-energy electrons hitting into the photons. One says the pulsar’s magnetic field accelerates the electrons, the other that it is the pulsar’s rapid rotation. Neither is easily harmonized with such high energy gamma rays.
–New Scientist