Pulsar star changes its beat – leaving astronomers puzzled
Posted by Xeno on July 31, 2012
Pulsars are the ‘beacons’ of space – tiny, burnt out stars, which emit regular pulses of gamma rays – regular, that is, until scientists found one with hiccups.
The pulsar J1838-0537 suddenly speeded up the rays it was blasting into space – and ‘glitched’, in a cosmic hiccup that scientists still don’t understand.
Even finding pulsars is extremely difficult – and the new discovery could throw light on these mysterious cosmic objects.
The odd new star was found as astronomers sifted astronomical data with supercomputers.
‘By employing new optimal algorithms on our ATLAS computer cluster, we were able to identify many previously-missed signals,’ says Bruce Allen, Director of the AEI.
Back in November 2011, Allen’s team announced the discovery of nine new Fermi gamma-ray pulsars, which had escaped all previous searches. Now the scientists have made a new extraordinary find with the same methods.
The name of the newly discovered pulsar – J1838-0537 – comes from its celestial coordinates.
‘The pulsar is, at 5,000 years of age, very young. It rotates about its own axis roughly seven times per second and its position in the sky is towards the Scutum constellation,’ says Holger Pletsch, a scientist in Allen’s group and lead author of the study which has now been published.
‘After the discovery we were very surprised that the pulsar was initially only visible until September 2009. Then it seemed to suddenly disappear.’
Only a complex follow-up analysis enabled an international team led by Pletsch to solve the mystery of pulsar J1838-0537: it did not disappear, but experienced a sudden glitch after which it rotated 38 millionths of a Hertz faster than before.
‘This difference may appear negligibly small, but it’s the largest glitch ever measured for a pure gamma-ray pulsar.’ …