New Class of Pulsars Discovered

xyz writes "NASA's Fermi Gamma-ray Space Telescope has discovered a new class of pulsars which emit purely in gamma rays. A pulsar is a rapidly spinning neutron star, and of the nearly 1,800 cataloged so far, only a small fraction emit at frequencies higher than radio waves. The gamma-ray-only pulsar, which lies within a supernova remnant known as CTA 1, is silent across parts of the electromagnetic spectrum where pulsars are normally found, indicating a new class of pulsars. It is located 'about 4,600 light-years away in the constellation Cepheus. Its lighthouse-like beam sweeps Earth's way every 316.86 milliseconds. The pulsar, which formed in a supernova explosion about 10,000 years ago, emits 1,000 times the energy of our sun.'"

Comments

Re:Would the Physicists Please Stand Up

[Gil-galad55]

The neutron star surface does emit thermal X-rays because it is hot. However, the electromagnetic radiation originates outside the neutron star, in its magnetosphere.

Pulsars have extremely strong magnetic fields and rotate anywhere from 1-to-1000 times a second. Just like an electric generator, this produces huge electromagnetic fields, and these accelerate electrons to very high energies indeed. These electrons than bang into photons and give them a large chunk of energy in a process called inverse Compton scattering, and we get gamma rays.

(This is the so-called leptonic channel; it is also possible some gamma rays are produced via pions, but the origin of the energy is the same: the huge electromagnetic fields generated by this spinning magnetic dipole.)

Re:Its proximity to earth is a good thing!

[Gil-galad55]

Sorry, its high luminosity is more than offset by its distance of kiloparsecs. The relevant quantity is flux, which goes like luminosity/distance^2.