Galactic geysers erupt halfway across the sky

Posted by Kate Taylor

Astronomers have discovered enormous outflows of charged particles from the centre of our galaxy, moving at supersonic speeds.

Using CSIRO's 64-m Parkes radio telescope, the international team found that the outflows extend 50,000 light-years out of the galactic plane - half the diameter of our galaxy itself.

"There is an incredible amount of energy in the outflows," says co-author Professor Lister-Staveley-Smith from the University of Western Australia.

"The source of the energy has been somewhat of a mystery, but we know there is a lot there, about a million times as much energy as a supernova explosion."

Luckily for us, the outflows aren't heading in our direction. They match previously identified regions of gamma-ray emission detected with NASA's Fermi Space Telescope and the 'haze' of microwave emission spotted by the Wilkinson Microwave Anisotropy Probe (WMAP) and Planck Space Telescope.

"Adding observations by the ground-based Parkes radio telescope to those made in the past by space telescopes finally allows us to understand how these enormous outflows are powered," says Professor Staveley-Smith.

It now appears that the outflows are driven by many generations of stars forming and exploding in the galactic center over the last hundred million years.

"We were able to analyse the magnetic energy content of the outflows and conclude that star formation must have happened in several bouts," says CAASTRO director Professor Bryan Gaensler.

And, he says, "We found that the outflows' radiation is not homogenous but that it actually reveals a high degree of structure - which we suspect is key to how the Galaxy's overall magnetic field is generated and maintained."