Astronomers have found two very different examples of extremely large, highly energetic plasma jets (nicknamed Porphyrion after a giant in Greek mythology) being emitted by a supermassive black hole. These jets, which stretch for 23 million light-years from end-to-end — enough to line up 140 Milky Way galaxies back-to-back— are also the longest giant particle colliders in the known universe. The discovery offers new clues about the impact of jets from black holes on the evolution of galaxy.
The Discovery of Porphyrion
The huge jets were found as part of a major survey of the sky using Europe’s LOw Frequency ARray (LOFAR) radio telescope. Intending to explore the cosmic web: the collection of filaments linking galaxies, led scientists unexpectedly to a series of super-long jet systems. It is the largest among over 10,000 giant jets uncovered by LOFAR, surpassing the previous record-holder, Alcyoneus.
To pinpoint the origin of these jets, the team utilized the Giant Metrewave Radio Telescope (GMRT) in India and additional data from the Dark Energy Spectroscopic Instrument (DESI) in Arizona. They traced the jets back to a supermassive black hole located in a galaxy about ten times more massive than the Milky Way and situated 7.5 billion light-years from Earth.
Significance of the Mega Jets
Porphyrion roamed the universe when it was roughly 6.3 billion years old – less than half of its current age, which is 13.8 billion-years-old . At this time, the filaments of the cosmic web were closer together and it was easier for large jets like these to influence the universe. The jets are so energetic that their total power is equivalent to trillions of suns, and they can stream over distances of well beyond their own host galaxy.
The finding indicates that huge black hole jets were far more common in the ancient universe than scientists had believed. Their ability to reach across vast distances implies they may have significantly impacted the formation and evolution of galaxies by distributing energy, cosmic rays, heavy elements, and magnetic fields throughout the cosmos.
Implications for the Universe’s Evolution
That Porphyrion was born in a radiative-mode active black hole, rather than jet-mode black holes we usually see, came as a surprise. This calls into question current models of black hole behavior and jet formation in the early universe. This raises the possibility that many more colossal jets are out there waiting to be discovered, and could help revise our model of how black holes influence their environment.
These jets are thought to have been a key ingredient in forging the cosmic web, influencing the formation of galaxies and the large-scale distribution of matter. These jets may even affect the ability of others stars to support life, by spreading out their magnetic fields and potentially affecting the conditions necessary for planets that look like Earth (solid with liquid water) to develop a protective magnetic shield.
Future Research Directions
The researchers want to investigate how these mega jets influence their surrounding, including their potential role in magnetizing the intergalactic medium. Discovering how jets such as Porphyrion can stay stable for billions of years could tell us much about black hole physics and the history of galaxies.
More of these giant jet systems are expected to be discovered as LOFAR surveys the sky more completely — so far it has only completed 15% of its intended sky survey. Such discoveries would help us better understand the past epochs of the universe and its basic principles of cosmic evolution.
