Their findings are certain to add to the debate, highlighted this week in Digital Journal, concerning the validity of the accepted Big Bang theory on the origin of the Universe.
The research team, led by scientists from Peking University in China and the University of Arizona (UA), discovered a quasar so bright it shines with the luminosity of 420 trillion suns. Quasars are the most powerful objects yet found in the universe, but the new discovery, now catalogued as SDSS J0100+2802, comfortably outshines any quasars so far found.
At the core of the quasar is a central black hole. Not just any black hole, however, for scientists estimate its mass as being the equivalent of 12 billion times that of our sun.
But it’s the object’s distance from Earth that makes the find so intriguing. SDSS J0100+2802 lies at a distance of 12.8 billion years from our solar system. That means astronomers are observing the quasar as it was almost 13 billion years ago, virtually at the dawn of time according to the Big Bang theory. The quasar must therefore have evolved just 900 million years after the Big Bang. The trouble is: how could an object so mind-bogglingly massive have come about in such a short period when compared with the estimated age of the universe?
The new discovery presents a major puzzle to the theory of black hole growth during the Universe’s formative eons according to Xiaohui Fan, Regents’ Professor of Astronomy at the UA’s Steward Observatory, co-author of the study.
“How can a quasar so luminous, and a black hole so massive, form so early in the history of the universe, at an era soon after the earliest stars and galaxies have just emerged?” queried Fan, adding “And what is the relationship between this monster black hole and its surrounding environment, including its host galaxy?
“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.”
The quasar dates back to a time close to the end of an important cosmic event dubbed the “Epoch of Reionization” by astronomers. During this period, which remains little understood, gas in the Universe went from being almost completely neutral to a state in which it became almost completely ionized.
The Epoch of Reionization was a watershed event that took place when the Universe was but a few hundred million years old, or roughly one-twentieth of its current age. It was a time when the first radiating objects formed. The Epoch is also inextricably linked to many fundamental questions concerning the evolution of the Universe and, with it, the formation of stars, quasars and galaxies.
The Epoch of Reionization marked the Universe’s cosmic dawn when light from the earliest generations of galaxies and quasars is thought to have ended the “cosmic dark ages” and transformed the Universe into how we see it today.
So where do quasars fit into all this? First discovered in 1963, quasars are the Universe’s most powerful transmitters, each beaming vast amounts of energy across space as the supermassive black hole a quasar’s center sucks in matter from its surroundings. So far, astronomers have discovered more than 200,000 quasars, with ages ranging from 0.7 billion years after the Big Bang right up to the present day.
But with a luminosity equivalent to 420 trillion suns and harboring a black hole of 12 billion solar masses, the new quasar is in a different league from all those thousands of quasars thus far discovered. It’s by far the most luminous quasar with the most massive black hole among all the known high redshift (very distant) quasars and about four times larger than the previous record holder.
“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 times heavier,” Fan said.
Feige Wang, a doctoral student from Peking University initially spotted this quasar and earmarked it for further study. That Wang spotted it using the 2.4-meter Lijiang Telescope in Yunnan, China made the find all the more remarkable since SDSS J0100+2802 is the only quasar ever discovered by a 2-meter telescope at such distance.
“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,” commented Wang.
After the initial discovery, two telescopes in southern Arizona, the 8.4-meter Large Binocular Telescope, or LBT, on Mount Graham and the 6.5-meter Multiple Mirror Telescope, or MMT, on Mount Hopkins, focused on the quasar to determine the distance and mass of the black hole. Additional observations, courtesy of the 6.5-meter Magellan Telescope in Las Campanas Observatory, Chile, and the 8.2-meter Gemini North Telescope in Mauna Kea, Hawaii, confirmed the results.
The research team plan further investigation of this, the brightest quasar in the early universe, using a number of international telescopes including the Hubble Space Telescope and the Chandra X-ray Telescope.
They hope their research will shed light on the physical processes that led to the formation of the earliest supermassive black holes.
Summing up the significance of the newly discovered quasar, Xue-Bing Wu, a professor of the Department of Astronomy, School of Physics at Peking University, said, “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.”
The research team’s findings were published in the journal Nature, Feb.26.