AAO Press Releases
Tuesday, 11 January 1999
Astronomers discover a puzzling quasar with a giant
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 wont 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