AAO Press Releases

A team of researchers from Australia, USA and the UK has discovered a quasar with one of the most luminous starbursts ever seen. 

Quasars are galaxies with extremely bright centres. Since their discovery in 1963, quasars have been a mystery because they emit astonishing amounts of energy from a very compact source. The most widely accepted explanation is that this energy is caused by the destruction of stars as they funnel down a black hole at the centre of the galaxy.

Over the past year, the team has discovered more than 100 new quasars. One of the newly discovered quasars was unique. The quasar, in the constellation of Sextans (the Sextant--- a small constellation near Leo), was observed with one of the most luminous starbursts ever seen. Starbursts are events that create stars in a huge firestorm, normally as a gas cloud collapses. This is a puzzle for astronomers: stars seem to be being created and destroyed in the same place.

The researchers believe that the amount of gas involved could be as much as one-tenth the mass of our own galaxy, the Milky Way. They also believe that as many as 50 million stars were created. Evidence suggests that the starburst grew out of the collision of two galaxies about 400 million years ago. The collision may have also provided the gases (mainly hydrogen and helium) to power the quasar.

One of the researchers, Dr Brian Boyle of the Anglo-Australian Observatory, suggests two explanations for the observation. ‘One possible explanation is that the quasar is ringed by the starburst; the other is that there are two merging galaxies, one has the starburst at its centre, the other a quasar at its centre. We won’t know until more detailed observations are made,’ he said.
 
 

An image is available at "http://www.llnl.gov/PAO/photos/QuasarStarburst.html
Image credit: Adam Stanford Lawrence Livermore National Laboratory