An international team of astronomers has discovered 83 new quasars from a time when the universe was just a tenth of the age it is today. Quasars – the bright centers of galaxies – are powered by extremely active supermassive black holes and this discovery gives us precious insights into the first billion years of the cosmos.
The findings are reported in five different papers, which detail the properties of the objects. The researchers revealed that the region they observed contains 100 quasars from the early universe, 17 of which we already knew about. They estimate that on average, the spacing between the supermassive black holes is about a billion light-years.
Among their discoveries, the team has found the second furthest quasar to date. Its light comes from a time when the universe was about 700 million years old.
“The quasars we discovered will be an interesting subject for further follow-up observations with current and future facilities,” team leader Yoshiki Matsuoka, from Ehime University in Japan, said in a statement. “We will also learn about the formation and early evolution of supermassive black holes, by comparing the measured number density and luminosity distribution with predictions from theoretical models.”
The researchers have also found the third most distant quasar at a similar distance to the second one. As reported in The Astrophysical Journal Letters, its distance is just one of its peculiar features. What makes this object special is the fact that it is not particularly luminous and not particularly massive. Its properties are comparable to what we observe in quasars in the current universe. The fact that they have a counterpart so early in the history of the cosmos is very important.
Exactly how supermassive black holes form continues to be a mystery. After the emission of the Cosmic Microwave Background, 370,000 years after the Big Bang, the universe entered the “Cosmic Dark Ages”, a time when no visible light was shining. After several hundred million years, the first stars began to form and matter assembled into the first galaxies. At the core of those galaxies were supermassive black holes gobbling up material with such energy that the galactic centers shone as quasars.
We think black holes form hierarchically. Small(ish) black holes, which could be the result of supernovas, merge and get bigger and bigger. But some of them are just too big to have formed like that in the time that's elapsed since the Big Bang. ULAS J1342+0928, the most distant quasar, is powered by a black hole 800 million times the mass of the Sun.
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