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Photo by Jenny
Mullins
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Just a few months after the Sloan Digital Sky
Survey's new mapping technology began operation in
New Mexico, Princeton graduate student Xiaohui Fan
and Assistant Professor of Astrophysical Sciences
Michael Strauss discovered the two most distant
quasars ever observed.
Quasars are compact,
luminous objects thought to be powered by
super-massive black holes. Redshift is the amount
by which light is shifted toward the red end of an
object's spectrum by the expansion of the universe.
Astronomers use redshift as a measure of the
distance of celestial objects: the higher the
redshift, the greater the distance and the younger
the universe when the light was emitted.
The newly discovered
quasars have redshifts of 5.0, 4.9 and 4.75, two
surpassing the previous record-holder: a
4.89-redshift quasar discovered in 1991 by Donald
Schneider, now of Pennsylvania State University;
Maarten Schmidt of California Institute of
Technology; and James Gunn, Princeton's Eugene
Higgins Professor of Astronomy, who built both the
camera and the spectrograph used by the Sky
Survey.
More...
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