Astronomers using several ground-based telescopes have spotted the most distant cosmic jet discovered so far. Its source is PSO J172.3556+18.7734, a radio-loud quasar located some 13 billion light-years from Earth and seen as it was when the Universe was only 780 million years old. While more distant quasars have been discovered, this is the first time astronomers have been able to identify the telltale signatures of radio jets in a quasar this early on in the history of the Universe.
Astronomers think that there’s a link between the rapid growth of supermassive black holes and the powerful radio jets spotted in quasars.
The jets are thought to be capable of disturbing the gas around the black hole, increasing the rate at which gas falls in.
Therefore, studying radio-loud quasars can provide important insights into how black holes in the early Universe grew to their supermassive sizes so quickly after the Big Bang.
PSO J172.3556+18.7734 is powered by a black hole about 300 million times more massive than our Sun that is consuming gas at a stunning rate.
“The black hole is eating up matter very rapidly, growing in mass at one of the highest rates ever observed,” said co-author Dr. Chiara Mazzucchelli, an astronomer at ESO.
“I find it very exciting to discover ‘new’ black holes for the first time, and to provide one more building block to understand the primordial Universe, where we come from, and ultimately ourselves.”
“The black holes at the cores of many of these very distant quasars are so massive that they challenge our understanding of how they could have grown in the relatively short time available to them that early in the Universe’s history,” said co-author Dr. Emmanuel Momjian, an astronomer at the National Radio Astronomy Observatory (NRAO).
“One possibility is that jets provided a mechanism that allowed the black holes to grow more quickly.”
“Finding a jet in a quasar at this epoch is an exciting clue about this question.”
“Jets have a role in regulating star formation and the growth of their host galaxies, so this discovery is valuable to understanding these processes in the early Universe,” said co-author Dr. Chris Carilli, also of NRAO.
“The jets at that time also propelled atoms and magnetic fields into what had been pristine space between the galaxies.”
PSO J172.3556+18.7734 was first recognized as a far-away quasar, after having been previously identified as a radio source, at the Magellan Telescope at Las Campanas Observatory.
“As soon as we got the data, we inspected it by eye, and we knew immediately that we had discovered the most distant radio-loud quasar known so far,” said lead author Dr. Eduardo Banados, an astronomer at the Max Planck Institute for Astronomy.
The astronomers used the X-SHOOTER instrument on ESO’s Very Large Telescope, NSF’s Karl G. Jansky Very Large Array, the Very Long Baseline Array, and the Keck telescope to determine key properties of PSO J172.3556+18.7734 such as the mass of the black hole and how fast it’s eating up matter from its surroundings.
“This discovery makes me optimistic and I believe — and hope — that the distance record will be broken soon,” Dr. Bañados said.
“Distant radio-emitting quasars at the beginning of the evolution of the cosmos also serve as beacons to study material that lies between Earth and the quasars.”
The discovery is reported in a paper in the Astrophysical Journal.
Eduardo Bañados et al. 2021. The Discovery of a Highly Accreting, Radio-loud Quasar at z = 6.82. ApJ 909, 80; doi: 10.3847/1538-4357/abe239