3 hours ago
Astronomers have just found 83 quasars, powered by supermassive black holes and dating back to the infancy of the Universe, when it was less than 10 percent of its current age.
Quasars are among the brightest objects in the Universe, extremely luminous galactic cores powered by actively feeding supermassive black holes. As material swirls around the black hole, its friction generates such intense radiation that it can be seen, even from billions of light-years away.
There's just one big problem. We think we know how black holes form - they are the collapsed cores of massive stars. And supermassive black holes can have up to billions of times the mass of the Sun.
This takes time, and requires copious amounts of matter. So how the heck did all these quasars pop up so early in the Universe's history?
"Understanding how black holes can form in the early Universe, and just how common they are, is a challenge for our cosmological models."
We've known there were quasars hanging out back then. The oldest one we've seen dates back to around 690 million years after the Big Bang, when the Universe was around five percent of its current age - and a few others have been spotted too.
But these - although still a puzzle - were thought to be relatively rare. So astronomers from Japan, Taiwan and the US broadened the search, using data from the Hyper Suprime-Cam mounted on the Subaru Telescope in Hawaii.
With this instrument, they could look for much fainter quasars than ones discovered previously. The oldest quasar they found was a massive 13.05 billion light-years away, tying for the second-most distant quasar ever found.
The Universe is thought to be about 13.8 billion years old, and the first stars - we think - didn't appear until around 500 million years after the Big Bang, after the neutral hydrogen of the early-early Universe was reionised. That just leaves a couple of hundred million years for the quasars to form.
The team's survey suggests that these objects were actually fairly abundant back then. They identified candidate quasars in the HSC data, then conducted a dedicated survey using multiple telescopes to obtain light signatures, or spectra, from these objects.