How common were black holes early in the universe’s history? We now have an idea: Astronomers have discovered 83 quasars powered by supermassive black holes in the distant universe, from a time when the universe was less than 10 percent of its present age.

“It is remarkable that such massive dense objects were able to form so soon after the Big Bang,” said Michael Strauss, a professor of astrophysical sciences at Princeton University and one of the co-authors of the study. “Understanding how black holes can form in the early universe, and just how common they are, is a challenge for our cosmological models.”

The discovery, made by astronomers from Japan, Taiwan, and Princeton University, increases the number of black holes known at that epoch considerably, provides new insight into the effect of black holes on the physical state of gas in the early universe in its first billion years.

Supermassive black holes, found at the centers of galaxies, can be millions or even billions of times more massive than the sun. While they are common today, it is unclear when they first formed, and how many existed in the distant early universe.

A supermassive black hole becomes visible when gas accretes onto it, causing it to shine as a “quasar.” Previous studies have been sensitive only to the very rare, most luminous quasars, and thus the most massive black holes. The new discoveries, detailed in a series of five papers published in The Astrophysical Journal and the Publications of the Astronomical Observatory of Japanprobe the population of fainter quasars, powered by black holes with masses comparable to most black holes seen in the present-day universe.

Light from one of the most distant quasars known, powered by a supermassive black hole lying 13.05 billion light-years away from Earth. The image was obtained by the Hyper Suprime-Cam (HSC) mounted on the Subaru Telescope. The other objects in the field are mostly stars in our Milky Way or galaxies along the line of sight. (Image Credit: National Astronomical Observatory of Japan)

The research team used data taken with the “Hyper Suprime-Cam” (HSC) instrument, mounted on the Subaru Telescope of the National Astronomical Observatory of Japan, located on the summit of Maunakea in Hawaii, and is surveying the sky over the course of 300 nights of telescope time, over five years.

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The team selected distant quasar candidates from the HSC survey data, tthen carried out an intensive observational campaign to obtain spectra of those candidates, using three telescopes: the Subaru Telescope; the Gran Telescopio Canarias on the island of La Palma in the Canaries, Spain; and the Gemini South Telescope in Chile.

The survey has revealed 83 previously unknown very distant quasars, and adding to the 17 quasars already known in the survey region, the researchers found there is roughly one supermassive black hole per cubic giga-light-year.

The sample of quasars in this study are about 13 billion light-years away from the Earth; in other words, we are seeing them as they existed 13 billion years ago.

This new discovery of quasars could play a role in determining when the first supermassive black hole appeared in the universe, according to the researchers.

“The quasars we discovered will be an interesting subject for further follow-up observations with current and future facilities,” said Yoshiki Matsuoka of Ehime University in Japan, who led the study. “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.”

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