Hubble spies brightest known quasar in the early universe

An artist’s impression of a an active galactic nucleus, or quasar, powered by a supermassive black hole. Image: ESA/Hubble, NASA, M. Kornmesser

Thanks to a chance alignment and the magnification provided by the gravity of an intervening galaxy, the Hubble Space Telescope has spotted the brightest quasar ever seen in the early universe, a galactic nucleus powered by a supermassive black hole several hundred million times the mass of the Sun and 11 trillion times as bright.

Light from the newly discovered quasar, known as J043947.08+163415.7, began its journey when the Universe was about one billion years old.

Despite its apparent brilliance, Hubble only managed to spot it thanks to a dim galaxy between the quasar and Earth that made the background object appear three times as large and 50 times brighter than it would be without the relativistic effects of gravitational lensing. The observed magnified luminosity was 600 trillion times that of the Sun.

The quasar J043947.08+163415.7 as imaged by the Hubble Space Telescope. The quasar is the brightest ever seen in the early universe, but it was only spotted thanks to the magnification provided by the gravity of an intervening galaxy. Image: NASA, ESA, X. Fan (University of Arizona)

Finding such a young powerhouse is “something we have been looking for for a long time,” said Xiaohui Fan of the University of Arizona, lead author of a paper describing the quasar. “We don’t expect to find many quasars brighter than that in the whole observable Universe!”

The data indicate the supermassive black hole at the heart of the quasar is pulling in matter at an extremely high rate and triggering the formation of up to 10,000 stars per year. In contrast, the Milky Way produces about one new star each year.

“Its properties and its distance make it a prime candidate to investigate the evolution of distant quasars and the role supermassive black holes in their centres had on star formation,” said co-author Fabian Walter of the Max Planck Institute for Astronomy in Germany.

Quasars in the early universe likely contributed to the period of reionization in the first billion years or so after the Big Bang when radiation from young stars and galaxies reheated neutral hydrogen and the Universe returned to an ionised plasma state. But more data is needed to nail down the sources of energy powering the reionisation.

Extensive studies of J043947.08+163415.7 are planned to do just that.