Post by glactus on Feb 25, 2010 6:33:15 GMT
Messier 80 globular cluster
Around a quarter of the globular star clusters in our Milky Way galaxy are invaders from other galaxies, according to a team of scientists from Swinburne University of Technology in Australia. In a paper accepted for publication in Monthly Notices of the Royal Astronomical Society, Swinburne astronomer Professor Duncan Forbes has shown that many of our galaxy's globular star clusters are actually foreigners - having been born elsewhere and then migrated to our Milky Way.
"It turns out that many of the stars and globular star clusters we see when we look into the night sky are not natives, but aliens from other galaxies," said Forbes. "They have made their way into our galaxy over the last few billion years."
Previously astronomers had suspected that some globular star clusters, which each contain between 10,000 and several million stars were foreign to our galaxy, but it was difficult to positively identify which ones.
The Hubble Space telescope
Using Hubble Space telescope data, Forbes, along with his Canadian colleague Professor Terry Bridges, examined globular star clusters within the Milky Way galaxy.
"Using this database we were able to identify key signatures in many of the globular star clusters that gave us tell-tale clues as to their external origin," Forbes said.
"We found that many of the foreign clusters originally existed within dwarf galaxies - that is 'mini' galaxies of up to 100 million stars that sit within our larger Milky Way.
"Although the dwarf galaxies are broken-up and their stars assimilated into the Milky Way, the globular star clusters of the dwarf galaxy remain intact and survive the accretion process."
Credits: Swinburne University of technology Australia
image Messier 80
thebigfoto.com/wp-content/uploads/2009/03/messier-80.jpg
This is part text only. See full text and all scientists involved at Spacedaily.com:
www.spacedaily.com/reports/Alien_Invaders_Pack_The_Milky_Way_999.html