France – Fermi satellite of NASA made it possible for CNRS researchers to discover two dozen pulsars emitting gamma rays.

A pulsar is a strongly magnetized core which remains after the explosion of a massive star. According to astrophysicists, the rapid rotation of these objects (neutron stars) involves creating beams of electromagnetic radiation. Like a spinning top, a pulsar slows down gradually and its radiation stops when it approaches the age of a few tens of million years. But if it pairs with a star, the matter lost by the latter may be favorable to revive its rotation with more energy. The star, called “millisecond pulsar”, revolves at a speed of ten thousand revolutions per minute and weighs more than the sun with a diameter of about ten kilometers.

1800 pulsars are known to date, of which one hundred of these are millisecond pulsars. The majority of these stars are studied by telescopes that detect their radio emission. Lucas Guillemot, Center for Nuclear Studies of Bordeaux-Gradignan, explains that until the use of Fermi satellite, the probability that the millisecond pulsars have the same mechanism of gamma radiation like the ordinary pulsars was uncertain.

The study of gamma radiation, however is of great interest: it allows to better understand the mechanisms involved in a pulsar. The radio energy emitted by a pulsar is low, whereas at least one tenth of the energy lost during deceleration of the big top is transmitted in gamma rays.

The Fermi Gamma-ray Space Telescope for NASA was created in collaboration with the U.S. Department of Energy. A mission is scheduled to last 5 to 10 years with major institutions and partners in France and in Germany, Italy, Japan, Sweden and the United States.

Fermi Space Telescope