Scientists discover `dramatic flares`

Last Updated: Friday, October 15, 2010 - 13:15

Washington: Scientists have discovered dramatic flares and bursts of energy emanating from a weakly magnetised, slowly rotating pulsar.
The international team of astrophysicists who made the discovery believes that the source of the pulsar`s power may be hidden deep within its surface.

Pulsars, or neutron stars, are the collapsed remains of massive stars. Although they are on average only about 30km in diameter, they have hugely powerful surface magnetic fields, billions of times that of our Sun.

The most extreme kinds of pulsars have a surface magnetic field 50-1000 times stronger than normal and emit powerful flares of gamma rays and X-rays. Named magnetars (which stands for "magnetic stars") by astronomers, their huge magnetic fields are thought to be the ultimate source of power for the bursts of gamma rays.

Theoretical studies indicate that in magnetars the internal field is actually stronger than the surface field, a property that can deform the crust and propagate outwards. The decay of the magnetic field leads to the production of steady and bursting X-ray emission through the heating of the neutron star crust or the acceleration of particles.

Now the research suggests that the same power source can also work for weaker, non-magnetar, pulsars. The observations, which were made by NASA``s Chandra and Swift X-ray observatories of the neutron star SGR 0418, may indicate the presence of a huge internal magnetic field in these seemingly less powerful pulsars, which is not matched by their surface magnetic field.

"We have now discovered bursts and flares, i.e. magnetar-like activity, from a new pulsar whose magnetic field is very low," said Dr Silvia Zane, from UCL``s (University College London) Mullard Space Science Laboratory.


First Published: Friday, October 15, 2010 - 13:15

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