Record-breaking black hole jets discovered in faraway galaxy

Astronomers say they have discovered the longest pair of black hole jets ever seen in the sky coming from a galaxy far, far away.

The record-breaking eruptions span 23 million light years from end to end, which is equivalent to lining up 140 Milky Way galaxies back to back, according to the researchers.

Named Porphyrion, after a giant in Greek mythology, these gigantic outflows – which shoot out from above and below a supermassive black hole – formed when the universe was a mere 6.3 billion years old, less than half its present age of nearly 14 billion years.

Understanding more about these colossal jets could help provide clues about magnetism – a phenomenon that is essential for life to thrive on Earth, the researchers said.

Although these are the largest jets from a black hole reported to date, scientists said jumbo jet systems may not be as rare as previously thought, with more than 10,000 megastructures discovered to date.

Dr Martijn Oei, a researcher at the California Institute of Technology in the US, said: “When we first found the giant jets, we were quite surprised.

“We had no idea that there were this many.”

The fierce jets, which originate around 7.5 billion light years away, have a combined power output equivalent to trillions of suns, the researchers said.

They come from a hefty galaxy about 10 times more massive than the Milky Way, they added.

Before Porphyrion, the largest confirmed jet system was Alcyoneus, also named after a giant in Greek mythology, which spans the equivalent of around 100 Milky Ways.

Researchers said their findings, published in the journal Nature, suggest these giant jet systems may have played a bigger role in the formation of ancient galaxies than previously believed.

Porphyrion existed during a time when the strands that connect and feed galaxies, known as the cosmic web, were closer together than they are now.

It means enormous jets like Porphyrion reached across a greater portion of the cosmic web than thought, the researchers said.

Porphyrion and other massive jets were found using Europe’s LOFAR (LOw Frequency ARray) radio telescopes which are located across seven countries in Europe, with the main antenna network in the Netherlands.

The team used machine-learning tools to scan the images for signs of these jets, with extra help from citizen scientists around the globe.

But they believe there may be a lot more colossal jets left to be found.

Dr Oei said: “We may be looking at the tip of the iceberg.

“Our LOFAR survey only covered 15% of the sky.

“Most of these giant jets are likely difficult to spot, so we believe there are many more of these behemoths out there.”

The researchers said it is not clear why the jets are so long but Martin Hardcastle, professor of astrophysics at the University of Hertfordshire, said it could be because the accretion – the process by which black holes consume surrounding material – would have been long and stable, allowing the jets to point in the same direction for billions of years.

He said: “If you think of these jets as blasting their way out through all of this material that is around them, then the more powerful the jet is, the faster they expand.

“You need the combination of high power and long life to get to these very large sizes.”

As a next step, Dr Oei wants to better understand how these gigantic jets spread magnetism – a force of nature produced by moving electric charges that also protects the Earth from radiation.

He said: “The magnetism on our planet allows life to thrive, so we want to understand how it came to be.

“We know magnetism pervades the cosmic web, then makes its way into galaxies and stars, and eventually to planets, but the question is: Where does it start? Have these giant jets spread magnetism through the cosmos?”

The research was funded by the Dutch Research Council, the European Research Council, the UK Science and Technology Facilities Council, the UK Research and Innovation Future Leaders Fellowship, and the European Union.