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Spitzer Sees Smoke From Galaxy Fire
Pasadena CA (SPX) Mar 16, 2006 A new infrared image from NASA's Spitzer Space Telescope shows an extremely active galaxy whose hot stars appear to be ejecting giant billows of smoky dust. The galaxy called Messier 82 - also known as the Cigar - had been known to host a hotbed of young massive stars, but the new Spitzer image, taken in infrared light, reveals for the first time a cloud of dust resembling the smoke surrounding those stellar fires. "We've never seen anything like this," said astronomer Charles Engelbracht of the University of Arizona in Tucson. "This unusual galaxy has ejected an enormous amount of dust to cover itself with a cloud brighter than any we've seen around other galaxies." Messier 82 is an irregular-shaped galaxy positioned on its side as a diffuse bar of blue light. Fanning out from its top and bottom, like the wings of a butterfly, are huge red clouds of dust thought to contain a compound similar to car exhaust. The smelly material, called polycyclic aromatic hydrocarbon, is found in tailpipes, barbecue pits and other places where combustion reactions have occurred. Stars also create PAH in enormous quantities, and their winds and radiation blow the material out into space. "Usually you see smoke before a fire, but we knew about the fire in this galaxy before Spitzer's infrared eyes saw the smoke," said David Leisawitz, a Spitzer program scientist at NASA Headquarters in Washington, D.C. The hazy clouds are some of the biggest ever seen around a galaxy, stretching out some 20,000 light-years away from the galactic plane in both directions, far beyond where stars are found. Previous observations of Messier 82 revealed two cone-shaped clouds of very hot gas projecting outward below and above the center of galaxy. Spitzer's sensitive infrared capability allowed astronomers to see the galaxy's dust. "Spitzer showed us a dust halo all around this galaxy," Engelbracht said. "We still don't understand why the dust is all over the place and not cone-shaped." Cone-shaped clouds of dust around this galaxy would have indicated its central massive stars had blown the dust into space. Instead, Engelbracht and colleagues think stars throughout the galaxy are the source. Messier 82 is about 12-million light-years away in the constellation Ursa Major � also known as the Big Dipper. It is a middle-aged galaxy, but nevertheless is undergoing a new burst of star birth, with the most intense star formation taking place at its core. Astronomers think the galaxy's interaction with its neighbor, the larger Messier 81, is fueling all the activity. The Milky Way, in comparison, is much less hectic, with most of its dust confined to the galactic plane. The Spitzer findings will appear in an upcoming issue of the Astrophysical Journal. Community Email This Article Comment On This Article Related Links Spitzer JPL NASA Space Telescope News and Technology at Skynightly.com
Spitzer Spies Double-Helix Nebula Near Milky Way Center
Pasadena CA (SPX) Mar 15, 2006Astronomers using the Spitzer Space Telescope report an unprecedented elongated double-helix nebula near the center of the Milky Way galaxy stretching at least 80 light-years in length. |
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