Astronomers have observed the largest ever jet observed shooting out from a black hole in the very early Universe.
Because light takes time to travel across the Universe, astronomers can effectively look back in time by peering deeper into space.
They can even see objects as they appeared shortly after the Big Bang.
The black hole jets in this study are seen as they appeared just 1.2 billion years after the Big Bang.
Observing the black hole jet
The jet was first identified by the international Low Frequency Array (LOFAR) Telescope, a network of connected radio telescopes located across Europe.
Then the team made follow-up observations in the near-infrared with the Gemini Near-Infrared Spectrograph (GNIRS), and in the optical with the Hobby Eberly Telescope.
The two-lobed jet spans at least 200,000 lightyears, which is twice the width of our Milky Way galaxy, making it the largest ever radio jet found so early in the Universe.
Astronomers say the discovery provides new insights into when the first jets formed in the Universe and how they affected the evolution of galaxies.
Black hole jets
Scientists know that most major galaxies have supermassive black holes at their centres.
These can be some of the brightest objects in the Universe, which goes against the common conception of black holes as being dark voids from which not even light can escape.
Cosmic matter falling into supermassive black holes at the centres of galaxies generates enormous friction, heating up as it does so.
This produces enormous amounts of energy, causing the centres of galaxies to glow brightly.
Bright galactic centres are known as quasars, and have been observed expelling matter into space in the form of jets.
Such jets can be detected with radio telescopes up to large distances, and while jets can be found in nearby galaxies in our local Universe, they've not been as easy to spot in the distant Universe.
Making the discovery
"We were searching for quasars with strong radio jets in the early Universe, which helps us understand how and when the first jets are formed and how they impact the evolution of galaxies," says Anniek Gloudemans, postdoctoral research fellow at NOIRLab and lead author of the study.
To measure key properties of the quasar, like its mass and the rate at which it's consuming matter, the team had to detect a specific wavelength of light emitted by quasars.
This is called the MgII (magnesium) broad emission line, and normally it's seen in ultraviolet.
But because the light from this quasar has travelled so far, for so long, the light has been stretched by the expansion of the Universe.
This has shifted it into the near-infrared wavelength range, meaning it was able to be detected with the GNIRS.
About the quasar
The quasar, named J1601+3102, formed when the Universe was less than 1.2 billion years old.
Some quasars can be billions of times the mass of our Sun, whereas J1601+3102 is 'just' 450 million times the mass of the Sun.
The double-lobed jets are not symmetrical, which means something in the surrounding environment could be affecting them.
"The quasar powering this massive radio jet does not have an extreme black hole mass compared to other quasars," says Gloudemans.
"This seems to indicate that you don’t necessarily need an exceptionally massive black hole or accretion rate to generate such powerful jets in the early Universe."
"It’s only because this object is so extreme that we can observe it from Earth, even though it’s really far away," says Gloudemans.
"This object shows what we can discover by combining the power of multiple telescopes that operate at different wavelengths."
"When we started looking at this object we were expecting the southern jet to just be an unrelated nearby source, and for most of it to be small. That made it quite surprising when the LOFAR image revealed large, detailed radio structures," says Frits Sweijen, postdoctoral research associate at Durham University and co-author of the paper.
"The nature of this distant source makes it difficult to detect at higher radio frequencies, demonstrating the power of LOFAR on its own and its synergies with other instruments."
Read the full paper at iopscience.iop.org/article/10.3847/2041-8213/ad9609
