Giant black holes yield cosmic 'baby picture'

UA astronomers recently identified the first two supermassive black holes ever witnessed in early stages of development.

"Our universe is about 13.7 billion years old, and these quasars (light generated by black holes) are 13 billion light-years away from us," the lead author of the study, Linhua Jiang, said in an e-mail interview.

"We are looking at a baby picture of the universe."

The project, led by UA astronomy professor Xiaohui Fan and funded by the NASA Jet Propulsion Laboratory, was completed last year and published in the journal Nature last month. The goal of the study was to gain a better understanding of the developmental stages of supermassive black holes.

It isn't certain how these massive bodies are formed, but they're found in the center of most galaxies and it's believed they're closely involved with the formation of their surrounding galaxies.

To get data on early stages of development, astronomers must look into distant galaxies billions of light-years from our own.

A light-year is the distance light travels in one year, about 6 trillion miles. For instance, since the supermassive black holes are about 13 billion light-years away, it took the light of the image 13 billion years to reach the Earth. Essentially, astronomers are looking back in time, at what how these objects appeared billions of years ago.

In the past, astronomers had been unable to distinguish many differences between younger, more distant black holes and older ones.

While the UA team was hopeful of finding something new, members expected their observations would yield similar results, Fan said.

"If you had asked me to bet at the time of the proposal, I would have that they would still be the same," he said.

The team used the Spitzer Space Telescope to more closely study 21 quasars discovered by the Sloan Digital Sky Survey over the last 10 years. Using the telescope's infrared capabilities, the astronomers noticed that two of the quasars were peculiar.

Until now, all black holes studied were surrounded by thick rings of dust produced by the debris of stars in the galaxy.

But these two distant black holes lacked the surrounding debris, suggesting that heavy elements like oxygen, iron and silicon had not yet developed in the young galaxy.

"That tells you that this black hole is in an environment that has not had a lot of things going on," Fan said.

While the astronomers don't yet know all of the implications of these dust-free black holes, they hope to gain more information in coming years.

"It's a very encouraging sign that we're on to something, but it leaves us with a puzzle," Fan said. "We still have to solve what exactly is going on."

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