A 'normal' galaxy that goes the distance - cluster over 11 billion light-years away - Brief Article

In the 1960s, astronomers identified a group of objects that rank among the most distant in the observable universe -- quasars that glow brilliantly in visible light and at radio wavelengths. Two decades later, researchers detected very distant galaxies that broadcast radio waves at high intensity. Now scientists have added a more mundane, less luminous object to their list of faraway bodies--a faint, radio-quiet galaxy that could be the youthful counterpart of such run-of-the-mill galaxies as our own Milky Way.

David Turnshek of the University of Pittsburgh and his colleagues spied the faint galaxy using the European Southern Observatory's 3.6-meter telescope at La Serena, Chile. Since looking into deep space is the same as peering back in time, the galaxy's great distance from Earth -- 11.4 billion light-years, according to one model -- indicates that astronomers are viewing the body as it appeared when the universe was just 13 percent of its current age. Moreover, the galaxy appears to reside amid a cluster of other bodies, including a huge cloud of hydrogen gas previously discovered by Cyril Hazard, also at Pittsburgh. Turnshek suspects the gas cloud, as glimpsed through the telescope, had just begun forming a new galaxy.

Other surveys that have scanned large regions of the sky for distant, quiescent galaxies have failed to find them because the faraway bodies appear extremely faint, Turnshek says. Rather than looking at a big swatch of the sky, Turnshek and his team limited their study to the vicinity of the large, distant hydrogen cloud. He suggests that distant hydrogen clouds may be part of galactic clusters and are probably associated with faint, run-of-the-mill galaxies.

If further observations reveal that clusters of "normal" galaxies were at least as common as quasars in the early universe, Turnshek notes, then cosmologists will have to explain how so many different galaxy types formed relatively soon after the Big Bang -- the giant explosion believed to have begun the expansion of the cosmos.

Turnshek described his group's work earlier this month at an American Astronomical Society meeting in Columbus, Ohio.

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