CHARLESTON, W.Va. -- Using the new, high-frequency capabilities of its recently installed W-Band receiver, the Green Bank Telescope has captured never-before-seen details of the starburst galaxy M82, located in the constellation Ursa Major, 12 million light-years from Earth.
Data produced through observations with the new receiver allows astronomers at Green Bank to see streamers of material fleeing the disk of the galaxy as well as concentrations of dense molecular gas surrounding pockets of intense star formation.
M82 is a classic example of a starburst galaxy -- a galaxy that produces new stars tens to hundreds of times faster than our own Milky Way, according to a release issued Monday by the National Science Foundation.
The addition of the W-Band receiver, capable of detecting the millimeter wavelength light emitted by molecular gas, makes the Green Bank Telescope the word's largest single-dish, millimeter-wave telescope.
"With this new vision, we were able to look at M82 to explore how the distribution of molecular gas in the galaxy corresponded to areas of intense star formation," said Amanda Kepley, a postdoctoral fellow at the National Radio Astronomy Observatory at Green Bank. "Having this new capability may help us understand why stars form where they do.
Kepley is the lead author of a paper accepted for publication in the Astrophysical Journal Letters.
Astronomers recognize that dense molecular gas is associated with areas of star formation, but the connection is poorly understood, and this relationship may be different in different types of galaxies. By creating wide-angle maps of the gas in galaxies, astronomers hope to better understand this complex interplay.
So far, observing such interaction has been difficult since molecules used to map the distribution of dense gas, like hydrogen cyanide, shine feebly in millimeter light. The new W-Band receiver allows the Green Bank Telescope to make highly sensitive, wide-angle images of gases in and around M82.
"The GBT data clearly show billowing concentrations of dense molecular gas huddled around areas undergoing bursts of intense star formation," Kepley said. "They also reveal giant outflows of ionized gas fleeing the disk of the galaxy. These outflows are driven by star formation deep within the galaxy."
The GBT's enhanced capabilities will help astronomers quickly survey entire galaxies and different parts within galaxies, according to the National Science Foundation. Such surveys would complement higher-resolution observations with the new Atacama Large Millimeter/Submillimeter Array telescope in Chile.
Astronomers created a composite image of the starburst galaxy M82 by charting the distribution of the molecular gas seen by the GBT and superimposing it over the background stars and dust seen by the Hubble Space Telescope.
Current plans call for the National Science Foundation to cut its ties to the Green Bank Observatory within the next four years, as part of a long-term cost-cutting overhaul. Last August, West Virginia University pledged to contribute $1 million during the next two years to support operations at the Pocahontas County observatory.
Reach Rick Steelhammer at rsteelham...@wvgazette.com or 304-348-5169.