Colossal distant black hole holds surprises about early universe


The black hole, announced today in the journal Nature, is the most distant ever found. We derive a significant neutral fraction, although the exact value depends on the modelling. In the coming years, astronomers hope to find more.

The most fundamental mystery is just what this black hole "ate" to become so huge.

After analyzing the quasar, the scientists found a lot of the hydrogen surrounding it is neutral, which suggests that the supermassive black hole formed during the reionization phase after the Big Bang. If it is located in a denser than average part of the universe, it could get an earlier start in life and grow more quickly.

"This black hole grew far larger than we expected in only 690 million years after the Big Bang, which challenges our theories about how black holes form", said study co-author Daniel Stern of NASA's Jet Propulsion Laboratory. The stars and interstellar dust are dominated by carbon, but heavier materials like magnesium, silicon, and nitrogen are also seen accreting into the black hole at the center. That helped scientists estimate that the stars turned on roughly when it began its journey - about 696 million years after the big bang.

The new black hole's mass, calculated after more observations, adds to an existing problem.

A team led by Eduardo Bañados, an astronomer at the Carnegie Institution for Science in Pasadena, found the new black hole by searching through old data for objects with the right color to be ultradistant quasars - the visible signatures of supermassive black holes swallowing gas.

In this approach, collapsing clouds in the early universe gave birth to overgrown baby black holes that weighed thousands or tens of thousands of solar masses.

In addition, he says, it looks like this black hole formed in a cosmic environment that was only just starting to be affected by light from the first stars. Bañados was looking in particular for quasars - some of the brightest objects in the universe, that consist of a supermassive black hole surrounded by swirling, accreting disks of matter. As the universe rapidly expanded, these particles cooled and coalesced into neutral hydrogen gas during an era that is sometimes referred to as the dark ages - a period bereft of any sources of light. They are regions of space where gravity is so strong that nothing-not even light-can escape.

Energy released at this time caused the universe to become "reionized"-the neutral hydrogen became excited and ionized, allowing photons to move through space and allowing the universe to become transparent".

It's a truly gargantuan black hole, some 800 million times the mass of our sun.

"It was the universe's last major transition and one of the current frontiers of astrophysics", Bañados said. After hundreds of millions of years, young stars or quasars emitted enough light to strip the electrons back off these atoms, dissipating the cosmic fog like mist at dawn. One scientist compared the team's discovery to finding a needle in a haystack - a very large and old haystack. "With several next-generation, even-more-sensitive facilities now being built, we can expect many exciting discoveries in the very early universe in the coming years".