Research Team Stumbles Upon Brightest Pulsar Recorded

Unusual source of x-rays will help astronomers learn how galaxies and black holes form.

A Texas Tech University astrophysicist was part of a team of researchers who recently discovered a new reason for mysterious ultraluminous X-ray sources to exist in the universe.

The discovery of the brightest pulsar ever recorded was made by accident during an observation aimed at looking at a recent supernova explosion in the nearby galaxy M82. The research was published in the Oct. 9 edition of the peer-reviewed journal Nature.

Tom Maccarone, an associate professor of physics at Texas Tech and co-author of the paper, said pulsars are dense stellar remnants left over from a supernova explosion. The one discovered burns with the light intensity of about 10 million suns. The discovery was made with NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR.

“For years, scientists believed the ultra-rare, ultraluminous X-ray sources were caused by black holes eating other nearby stars, accreting gas and emitting a light that’s millions of times brighter than our sun,” Maccarone said. “That may still be the case with most. However, we discovered that one of these entities, of which there are about 20 known so far, is actually a pulsar. The one we studied was in the M82 galaxy 12 million light-years away, and the X-ray emission we saw showed a pulse. That told us this was actually a pulsar – a star with about the mass of the sun packed into a region about the size of a city. The light it was emitting had a sort of lighthouse effect, and there was a magnetic pole and rotation pole. The light would come around periodically. That’s why this one is so special.”