Scientists see singular cosmic act of rebirth

May 22nd, 2009 - 12:19 pm ICT by ANI  

Washington, May 22 (ANI): An international team of astrophysicists has observed a singular cosmic act of rebirth, by seeing the transformation of an ordinary, slow-rotating pulsar into a superfast millisecond pulsar with an almost infinitely extended lifespan.

The discovery was made during a large radio sky survey by astrophysicists at McGill University, the University of British Columbia (UBC), West Virginia University, the US National Radio Astronomy Observatory (NRAO) and several other institutions in the US, the Netherlands and Australia.

“This survey has found many new pulsars, but this one is truly special - it is a very freshly ‘recycled’ pulsar that is emerging straight from the recycling plant,” said astrophysicist Anne Archibald of the McGill Pulsar Group.
Pulsars are rapidly rotating, highly magnetized neutron stars, the remnants left after massive stars have exploded as supernovae.

Pulsars emit lighthouse-like beams of radio waves that sweep around as the star rotates.

Most rotate relatively slowly, ten times a second or less, and their magnetic fields ordinarily slow them down even further over the course of millennia.

Millisecond pulsars, however, rotate hundreds of times a second.

“We know normal pulsars typically pulsate in the radio spectrum for one million to ten million years, but eventually they slow down enough to die out,” said Victoria Kaspi of the McGill Pulsar Group.

“But, a few of these old pulsars get ‘recycled’ into millisecond pulsars. They end up spinning extremely fast, and then they can pulsate forever. How does nature manage to be so green?” she added.

It has long been theorized that millisecond pulsars are created in double-star systems when matter from the companion star falls into the pulsar’s gravity well and increases the rotation speed, but until now, the process has never been observed directly.

“We’ve seen systems that are undergoing spin-up, because when the matter is falling in, the stars get really bright in X-rays and they’re easy to see,” said Archibald.

“But, we’ve never seen radio pulsations from these stars during the process of spin-up. At last, we’ve found a true radio pulsar that shows direct evidence for having just been recycled,” she added.

The pulsar found by the survey team was fortuitously observed by an independent, optical research group to have had swirling matter surrounding it roughly a decade ago.

“In other words, for the first time, we have caught a glimpse at an actual cosmic recycling factory in action,” said Ingrid Stairs of UBC.

“This system gives us an unparalleled cosmic laboratory for studying how millisecond pulsars evolve and get reborn,” Stairs added. (ANI)

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