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Cosmic survey yields surprise.

When astronomers last year used a balloon-borne telescope to observe a small patch of sky in the far infrared, they were intent only on studying the faint microwave glow left over from the birth of the universe. But they now report that their 10-hour survey may have uncovered a puzzling new class of objects.

Edward S. Cheng of NASA's Goddard Space Flight Center in Greenbelt, Md., and his colleagues launched the far-infrared telescope to search for faint hot and cold spots in the cosmic microwave background. Such temperature fluctuations may signify primordial lumps that later gave rise to the present-day collection of galaxies and galaxy clusters.

The team's experiment, known as the Medium-Scale Anisotropy Measurement (MSAM), measured the temperature variation in the microwave background over patches of sky 0.5 degrees in diameter--the width of the full moon on the sky. MSAM found that the temperature varied by about one part in 100,000. But MSAM also detected two luminous, point-like sources of radiation that don't appear to be part of the microwave background.

Moreover, the sources don't correspond to any objects compiled in well-known infrared and radio-wave catalogs, says Cheng. He adds that MSAM detected these puzzling emissions only at the two longest far-infrared wavelengths in the survey -- 1.1 and 1.8 millimeters. Cheng speculates that the sources might be distant, radio-quiet quasars. Alternatively, the emissions may stem from an exotic celestial object that either doesn't emit radio waves below a certain frequency or is surrounded by material that absorbs radio waves. "This is the beginning of a hunting expedition," he notes.

Cheng says he's of two minds about the findings. On the one hand, they could represent the first celestial sources discovered by observing in the far infrared. On the other hand, if the sky is littered with such point-like sources, it will make the task of deciphering the structure of the microwave background at small angular scales far more difficult.
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Title Annotation:Medium-Scale Anisotropy Measurement experiment detected temperature variations that may be due to a new class of celestial object
Author:Cowen, Ron
Publication:Science News
Article Type:Brief Article
Date:Jul 3, 1993
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