Light-years away: Graduate student finds distant celestial object

A glimpse into the universe's beginning lies with a discovery by Xiaohui Fan, a graduate student in the University's astrophysics department.

On the evening of April 6, Fan and his colleagues located a "Redshift 5.8 Quasar," which is considered to be the most distant known celestial object, surpassing the previous record holder — a galaxy discovered last year by researchers in Hawaii and Cambridge, England.

A quasar is an extremely compact, luminous object scientists believe to be powered by black holes as massive as the size of one billion of Earth's suns. The Redshift 5.8 Quasar is part of the Sextans constellation and is estimated to be about 12 billion years old. The universe's age is believed to be 13 billion years old.

"It comes from a time when the universe was only five percent of its current age, in its infancy," Fan said. "The significance of the discovery is this object must be one of the first generation of objects formed in the universe, not very much after the so-called 'big bang.' "

The discovery of the quasar represents a positive step toward unlocking the mysteries of the universe, Fan said. "To study them is really [to study] the childhood of the universe when the stars and galaxies we see today were first formed," he explained.

'Needle out of a haystack'

Finding this quasar was no easy task. The first step was to measure the colors of many celestial objects from digital pictures taken by the Sloan Digital Sky Survey, an international team of scientists trying to map out half the northern sky. Fan described this first step as "the most difficult part, really like picking a needle out of a haystack."

Next, the team recorded a light spectrum of the object and used it to measure the distance between the quasar and Earth. This process took place in Mauna Kea, Hawaii, using the world's largest 10-meter Keck telescope, Fan said.

Fan said he and his colleagues realized immediately what they were looking at and recalled that the discovery was a "time of excitements." But, he emphasized, "there was no time to celebrate." Fan's research required more observations that same night and will likely continue for years.

Only a small percentage of the data from the Sloan survey has yet been analyzed. But with this discovery, the possibilities become limitless. "What kind of science we can get at the end of our project is really beyond our imagination now, and the best is certainly yet to come," Fan said.