April 30, 2009

Astronomers discover unusual dwarf galaxy

A U.S. astronomer says he discovered a galaxy in which gas is distributed over a much larger area than researchers expected to find.

Macalester College Professor John Cannon said the giant disk dwarf galaxy he discovered has the largest size difference between stars and gas of any known galaxy. That finding, he said, is important for furthering the understanding of how galaxies form and how they remain stable over time.

Cannon said data from the Kitt Peak National Observatory in Arizona and the Very Large Array telescope in New Mexico show the galaxy -- named ADBS1138 -- has a very small and compact stellar component.

Because the stars are so compact, we expected to see a system that has a similarly compact gaseous disk, said Cannon. To our surprise, the gaseous disk is enormous -- some 44 times larger than the size of the galaxy as seen in stars.

The research by Cannon, Jessica Rosenberg of George Mason University and John Salzer of Indiana University is to appear in the May 10 edition of The Astrophysical Journal.