Hertfordshire astrophysicist helps uncover 10,000 black hole jets, including largest ever seen
Jets are said to shoot out of massive black holes at the speed of light, taking the magnetic field out of them and pushing it into outer space
An international team of astronomers, including Professor Martin Hardcastle from the University of Hertfordshire, has uncovered more than 10,000 black hole jets, with one pair setting the record as the largest ever observed.
Spanning 23 million light-years—equivalent to lining up 140 Milky Way galaxies back-to-back—this colossal jet system, nicknamed "Porphyrion," was found using the LOFAR (Low Frequency Array) radio telescope in Europe.
Professor Hardcastle, an expert in radio astronomy and high-energy astrophysics, co-authored the study, which was led by Dr. Martijn Oei of Caltech.
The findings, recently published in Nature, reveal that the gigantic jets are located 7.5 billion light-years from Earth.
This means the structure existed when the universe was just 6.3 billion years old, less than half its current age of 13.8 billion years.
Pr Hardcastle said: "These giants were known before we started the campaign, but we had no idea that there would turn out to be so many.
"Usually, when we get a new observational capability, such as LOFAR’s combination of a wide field of view and very high sensitivity to extended structure, we find something new, but it was still very exciting to see so many of these objects emerging."
The discovery of Porphyrion was part of a larger effort to systematically search for black hole jets across the sky.
To achieve this, the team used three different approaches: manually inspecting radio images, employing machine-learning tools, and enlisting the help of citizen scientists around the world.
"We had about a million views of our citizen science projects trying to identify these large, complicated structures," Pr Hardcastle said.
This helped the team confirm the existence of over 10,000 such systems.
What makes Porphyrion particularly fascinating is its immense size and power, with its jets stretching beyond the host galaxy by millions of light-years.
These jets, capable of shooting out particles at speeds close to the speed of light, are driven by the gravitational energy of a supermassive black hole.
W. M. Keck Observatory in Hawaii confirmed that Porphyrion's jets originated from a radiative-mode supermassive black hole, a type more common in the early universe.
"This is a surprising finding," said Dr. Oei, the study’s lead author. "We didn’t expect a radiative-mode black hole, known for producing bright radiation, to be capable of generating jets this large and powerful."
This raises the possibility that there may be many more such megastructures yet to be found in the distant universe.
This investigation is part of a long-standing tradition of astrophysics research at the University of Hertfordshire.
The institution has made significant contributions to the understanding of far-off galaxies, the magnetic fields of the universe, and the hidden stars within our Milky Way.
In May, former Herts postgraduate student Dr. Beatriz Mingo received the prestigious Ernest Rutherford Fellowship for her ground-breaking research on new populations of black hole jets.
Pr Hardcastle said: "What we’re learning from the large number of giants is that this must be a relatively common occurrence.
"It’s great when we do something that catches the eye and people want to know about it."
The discovery of Porphyrion and its companion jets represents not just a scientific breakthrough, but also a reminder of how much remains to be uncovered in the distant cosmos.