When is two million light years just a whisker鈥檚 breadth? When you鈥檙e talking about which of two quasars 13 billion light years away is the most distant ever discovered. The new record breaker, just, was announced today by Chris Willott of the University of Ottawa in Canada.
Even this incremental increase in distance promises some new insight into the 鈥渄ark ages鈥� of the early universe.
For nearly a billion years, the first stars and galaxies were concealed behind a light-absorbing veil of hydrogen atoms, until ultraviolet light from hot young stars and matter falling into the giant black holes we call quasars ionised the hydrogen to clear the haze.
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The new quasar is the oldest yet found, and astronomers hope it will help reveal how stars, galaxies, and quasars formed during these dark ages.
The previous record holder was spotted by the Sloan Digital Sky Survey. Its light was extremely red-shifted 鈥� stretched by the ongoing expansion of the universe. The red shift is 6.41, meaning the wavelength of its light has been stretched by 641%.
Ancient object
A new survey with the 3.5-meter Canada-France-Hawaii Telescope can spot much fainter quasars than the Sloan survey, which used a smaller, less sensitive telescope, says Willott. That鈥檚 important because smaller quasars are more common.
He told the Canadian Astronomical Society meeting in Kingston, Ontario, that the survey had found four quasars beyond a red-shift of 6, including one, given the memorable title CFHQS J2329-0301, at a record red-shift of 6.43. That means we鈥檙e seeing it just 870 million years after the big bang.
The new black hole weighs in at 500 million solar masses. 鈥淭heoretically, it鈥檚 very hard to create such a big black hole so early in the universe,鈥� Willott told New 杏吧原创.
The discovery will also help to reveal how many stars and other quasars were lighting up around that time, and ionising hydrogen gas. A detailed spectrum shows that the hydrogen haze around the new quasar had started to clear even before it turned on, but on its own that doesn鈥檛 prove the dark ages were ending across the entire cosmos.
鈥淵ou need a large sample of quasars to get firm conclusions,鈥� says Avi Loeb of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, US. Willott hopes his survey will find about 11 more, raising the total close to the 25 to 30 thought to be needed.
