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Mauna Kea telescopes find earliest-known quasar

By Gregg K. Kakesako

POSTED:
LAST UPDATED: 12:50 p.m. HST, Jun 29, 2011


An international team of astronomers using telescopes on Mauna Kea have discovered the most distant and earliest-known quasar, a bright, starlike object believed to have formed just after the universe was created.

Light from the quasar — created by gas falling into a supermassive black hole — took nearly 13 billion years to reach Earth, meaning it existed when the universe was only 770 million years old. Until now, the most distant quasar ever seen sent light 870 million years after the Big Bang, the explosion believed to have created the universe 13.7 billion years ago.

The quasar, named ULAS J1120+0641, was discovered in images from the United Kingdom Infrared Telescope Infrared Deep Sky Survey — a new map of the sky at infrared wavelengths.

"It's like sifting for gold. You're looking for something shiny," said lead researcher Daniel Mortlock, an astrophysicist at Imperial College in London. 

The infrared sky survey was conducted at the United Kingdom Infrared Telescope and confirmed by observations with the Gemini North telescope, both on Mauna Kea in Hawaii. The results are in the June 30 issue of the Journal Nature.

Since quasars are so luminous, they guide astronomers studying the conditions of the cosmos after the Big Bang. Researchers are constantly trying to outdo one another in their quest to see the universe as an infant. The deeper they peer into space, the further back in time they are looking. 

"What is particularly important about this source is how bright it is," Mortlock said. "It's hundreds of times brighter than anything else yet discovered at such a great distance. This means that we can use it to tell us for the first time what conditions were like in the early universe."

To scientists' surprise, the black hole powering this quasar was 2 billion times more massive than the sun. How it grew so bulky so early in the universe's history is a mystery. Black holes are known to feed on stars, gas and other matter, but their growth was always thought to be slow. 

The light from the quasar started its journey toward us when the universe was only 6 percent of its present age, 770 million years after the Big Bang."This gives astronomers a headache," says "It's difficult to understand how a black hole a billion times more massive than the sun can have grown so early in the history of the universe. It's like rolling a snowball down the hill and suddenly you find that it's 20 feet across."

One of the world's largest telescopes dedicated solely to infrared astronomy, the 12.5-foot United Kingdom Infrared Telescope near the summit of Mauna Kea at an altitude of 13,760 feet above sea level. It is operated by the Joint Astronomy Centre in Hilo on behalf of the UK Science and Technology Facilities Council. The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is on Mauna Kea (Gemini North) and the other telescope in central Chile (Gemini South).

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The Associated Press contributed to this story.






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