NASA-International Space Station

A galaxy located billions of light-years away is imposing the attention of NASA''s Fermi Gamma-ray Space Telescope and astronomers around the globe. The galaxy is now the brightest source in the gamma-ray sky more than ten times brighter than it was in the summer.

Astronomers identify the object as 3C 454.3, an active galaxy located 7.2 billion light-years away in the constellation Pegasus. But even among active galaxies, it is extraordinary.

"We are looking right down the barrel of a particle jet powered by the galaxy's super massive black hole," said Gino Tosti at the National Institute of Nuclear Physics in Perugia, Italy. "Some change within that jet but we don't know what is probably responsible for these flares."

Blazars, like many active galaxies, emit oppositely directed jets of particles traveling close to the speed of light when matter falls toward their central super massive black holes. What makes a blazar so bright in gamma rays is its direction: One of the jets happens to be aimed straight at us.

Most of the time, the brightest persistent source in the gamma-ray sky is the Vela pulsar, which at a distance of about 1,000 light-years lies virtually next door.

According to Massimo Villata at Italy''s Torino Observatory, 3C 454.3 also is flaring at radio and visible wavelengths, if less noticeably. "In red light, the blazar brightened by more than two and a half times to magnitude 13.7, and it is also very bright at high radio frequencies."