Astronomers have discovered 83 quasars powered by supermassive black holes 13 billion light-years away from the Earth, from a time when the universe was less than 10 per cent of its present age. A professor at Princeton University in the US, Michael Strauss said, it is remarkable that such massive dense objects were able to form so soon after the Big Bang. He said in a statement that the understanding how black holes can form in the early universe, and just how common they are, is a challenge for the cosmological models.

This finding, published in The Astrophysical Journal, increases the number of black holes known at that epoch considerably, and reveals, for the first time, how common they are early in the universe’s history. In addition, it 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 prevalent 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 probe the population of fainter quasars, powered by black holes with masses comparable to most black holes seen in the present-day universe.