Ancient galaxy being
studied atop Mauna Kea
Astronomers working with telescopes atop Hawaii's Mauna Kea are studying a galaxy they say is the biggest, brightest, hottest and one of the most ancient star-forming regions yet viewed in the universe.
The explosive galaxy of more than a million hot stars normally could not be examined because its stars were born so long ago and so far away. But a combination of powerful telescopes and natural "gravitational lensing" that enhances the earth's view of the object are credited for the scientific advance.
Discovery of the Lynx Arc cluster, a million times brighter than the somewhat similar Milky Way cluster known as the Orion Nebula and 8 million light-years farther away, was announced yesterday by the W.M. Keck Observatories on the Big Island and reported in the latest issue of the Astrophysical Journal.
Stars in the galaxy are bigger than stars much older and closer, scientists say. Twelve million light-years from Earth, the growth spurt of stars is believed to have occurred when the universe was just 2 billion years old, or about 15 percent of its current age.
The cluster is not unique, said astronomer Bradford Holden, of the University of California's Lick Observatory at Santa Cruz, but the clear view of it is.
Gravitational pull of the light coming from a nearer galaxy, called "gravitational lensing," naturally stretches and magnifies the image scientists see of the star cluster, creating a sort of natural telescope that has made the Lynx Arc brighter and more visible than other similar clusters, Holden said in a telephone interview.
Originally, the Lynx Arc appeared as a "puzzling red arc" behind the nearer galaxy, he said.
"The potentially cool thing for me is that because it has certain gross properties that make it like a whole lot of other objects, it could be that every galaxy goes through a phase like this, including our own Milky Way," he said.
He described the view of the cluster aided by gravitational lensing as "a lucky coincidence."
Discovery of the star cluster is credited to an international team of astronomers and researchers including Holden and led by Bob Fosbury, of the European Space Agency's Space Telescope-Eurolean Coordinating Facility in Germany. The agency used the dual Keck telescopes atop Mauna Kea for part of its research.
Fosbury, in a release from the observatory, said the discovery of the cluster takes scientists a step closer to seeing the earliest stars believed to have formed after creation of the universe, as much as 1.8 billion years earlier than the Lynx Arc.
"This remarkable object is the closest we have come so far to seeing what such primordial objects might look like when our telescopes become powerful enough to see them," Fosbury said.
