A team of international astronomers have been hunting for ancient supermassive black holes – and they hit the motherlode, discovering 83 previously unknown quasars.
The universe is full of supermassive black holes, monstrous versions of the humble, everyday black hole, containing millions of millions or billions of times that of our sun. These huge cosmic beasts generate gigantic gravitational effects, so they often find supermassive black holes that hide in the center of galaxies orbit by billions of stars. This is exactly what happens in our home Milky Way galaxy.
To find them lurking in the most distant parts of the universe, you must study the light of the gases that grow and swirl around them. Because we can't see a black hole, but we can see the light, we designate these powerful light sources as "quasars". The eyepiece of a telescope may seem more like the stars ̵
The Japanese team transformed the ultra-powerful "Hyper Suprime-Cam", mounted on the Subaru Telescope in Hawaii, towards the darkest corners of the cosmos, which guarded the sky for a period of five years. By studying the snapshots, they were able to choose potential quasar candidates from the dark. In particular, their method of probing the populations of supermassive black holes similar in size to those we see in today's universe has given us a window on their origins.
After identifying 83 potential candidates, the team used a suite of telescopes to confirm their results. The quasars they tore come from the primordial universe, about 13 billion light years away. In practice, this means that researchers are looking at the past, at objects that form less than a billion years after the Big Bang.
"It is extraordinary that such dense and massive objects were able to form so soon after the Big Bang," said Michael Strauss, co-author of the paper, in a press release.
Scientists are not sure how black holes formed in the primordial universe, so being able to locate them so far back in time provides new avenues of exploration. In particular, the researchers discover a quasar with a brightness much lower than what they expected. The characteristics of that particular quasar, HSC J124353.93 + 010038.5, have been reported in The Astrophysical Journal Letters in February.
"The quasars we have discovered will be an interesting topic for further follow-up observations with current and future structures," said Yoshiki Matsuoka, chief researcher, in a statement.