* Astronomy

A blitz of star formation is taking place in a where two galaxies have collided, the Hubble Space Telescope has revealed. Researchers say studying the collision should shed light on the early universe, when such mergers were commonplace.

The intense star birth is occurring in a galaxy called Arp 220, which formed from the collision of two galaxies about 700 million years ago. Hubble's Advanced Camera for Surveys (ACS) has found more than 200 dense clusters of stars within a region just 5000 light years across, or about 5% of the width of the Milky Way.
The most massive cluster contains the mass of 10 million Suns – twice as much material as found in the largest star cluster in the Milky Way.


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"This is star birth in the extreme. Our result implies that very high star-formation rates are required to form supermassive star clusters" - Christine Wilson, team leader, McMaster University in Hamilton, Canada.

Arp 220 lies about 250 million light years away and is the brightest of three galactic mergers closest to the Earth. As such, it provides a relatively local laboratory for the study of galactic mergers. These occurred frequently billions of years ago, when our expanding universe was smaller and more densely packed.
Observations with ACS and an infrared camera called NICMOS (Near Infrared Camera and Multi-Object Spectrometer) suggest the star clusters range in age from less than 10 million years old to about 500 million years old. If the galaxy continues to produce star clusters at its current rate, it will exhaust all of its gas in about 40 million years.
A study based on the newly released image that appeared in the April 20 issue of the Astrophysical Journal.

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-- Edited by Blobrana at 20:15, 2006-06-13