A group of astronomers from the United States, China, Chile, and Australia, has discovered the brightest quasar in the early Universe, powered by the most massive black hole yet known at that time.
This image shows SDSS J0100+2802 (center), the brightest quasar in the early Universe. Image credit: Sloan Digital Sky Survey.
The ultraluminous quasar, named SDSS J010013.02+280225.8 (for short SDSS J0100+2802), was found at a redshift of z=6.30.
This is a measurement of how much the wavelength of light emitted from it that reaches us on Earth is stretched by the expansion of the Universe. As such, it can be used to calculate the quasar’s age and distance from our planet.
SDSS J0100+2802 was formed only 900 million years after the Big Bang and now lies at a distance of 12.8 billion light-years.
With a luminosity of 420 trillion that of our own Sun’s, it is seven times brighter than the most distant quasar known.
“This quasar is very unique. Just like the brightest lighthouse in the distant Universe, its glowing light will help us to probe more about the early Universe,” said Dr Xue-Bing Wu of Peking University and the Kavli Institute of Astronomy and Astrophysics, who is the first author of the paper published in the journal Nature.
There are only 40 known quasars have a redshift of higher than 6, a point that marks the beginning of the early Universe.
SDSS J0100+2802 hosts a monstrous black hole about 12 billion times the mass of our Sun, proving it to be the most luminous quasar with the most massive black hole among all the known high redshift quasars.
“By comparison, our own Milky Way Galaxy has a black hole with a mass of only 4 million solar masses at its center; the black hole that powers this new quasar is 3,000 time heavier,” said co-author Dr Xiaohui Fan from the University of Arizona.
“The discovery challenges theories of how black holes form and grow in the early Universe. Forming such a large black hole so quickly is hard to interpret with current theories,” said co-author Dr Fuyan Bian of the Australian National University.
A quasar is an extremely bright cloud of material in the process of being sucked into a black hole. As the material accelerates towards the black hole it heats up, emitting an extraordinary amount of light which actually pushes away material falling behind it.
This process, known as radiation pressure, is thought to limit the growth rate of black holes.
“However this black hole at the center of the quasar gained enormous mass in a short period of time,” Dr Bian said.
“This ultraluminous quasar with its supermassive black hole provides a unique laboratory to the study of the mass assembly and galaxy formation around the most massive black holes in the early Universe,” added Dr Fan.
“This quasar was first discovered by our 2.4-m Lijiang Telescope in Yunnan, China, making it the only quasar ever discovered by a 2-m telescope at such distance, and we’re very proud of it,” explained study co-author Feige Wang, a doctoral student from Peking University.
“The ultraluminous nature of this quasar will allow us to make unprecedented measurements of the temperature, ionization state and metal content of the intergalactic medium at the epoch of reionization.”
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Xue-Bing Wu et al. 2015. An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30. Nature 518, 512–515; doi: 10.1038/nature14241
