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Galaxies in the early universe DID contain central black holes
Thursday, 16 June 2011 11:04
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Astronomy - Galaxies

Did the galaxies evolve around black holes, or did the galaxies create the central black holes? This question has haunted astronomers for years, but Hawaiian astronomers are now one step closer to the answer:

Using the most sensitive X-ray image ever taken, University of Hawaii astronomer Ezequiel Treister and colleagues have found the first direct evidence that black holes existed when the Universe was less than a tenth of its present age.

30%-100% of the 200 distant galaxies they observed contained a central black hole that was voraciously consuming the gas and stars that surrounded them.

This discovery was made with NASA’s orbiting Chandra X-ray Observatory.

“Black holes are objects whose gravity is so strong that not even light can escape from them. Until now, we had no idea what the black holes in these early galaxies were doing - or if they even existed,” said Treister, lead author of the study that appears in this week’s Nature. “Now we know they are there and they are growing like gangbusters.”

“It appears we’ve found a whole new population of baby black holes,” said co-author Kevin Schawinski of Yale University. “We think these babies will grow by a factor of about a hundred or a thousand, eventually becoming like the giant black holes we see today almost 13 billion years later.”

“These observations indicate that extremely massive black holes already existed as early as 700-800 million years after the Big Bang, which suggests that either they were born massive to start with, or they experienced rapid growth bursts,” said Kevin Schawinski, a Yale astronomer who contributed to the discovery. “Either scenario tells us much more than we previously knew, which is very exciting.This finding tells us there is a symbiotic relationship between black. holes and their galaxies that has existed since the dawn of time,”

A population of very young black holes in the early Universe had been predicted, but not yet observed. Detailed calculations show that the total amount of black hole growth observed by this team is about a hundred times higher than recent estimates.

Because these very young black holes are nearly all enshrouded in thick clouds of gas and dust, optical telescopes frequently cannot detect them.  However, the high energies of X-ray light can penetrate these veils, allowing the black holes inside to be studied.

Source: Hawaii Univsersity