Sep 23, 2024 15:00:00

The largest jet ever recorded, measuring 23 million light years in length, is discovered to be emanating from a black hole 7.5 billion light years away.

by S. Dagnello (NRAO/AUI/NSF)

It is said that black holes have extremely strong gravity, which distorts the space-time around them so much that not only matter but even light cannot escape. However, black holes not only suck in the matter around them with their strong gravity, but they also sometimes exhibit a phenomenon called a '

jet ,' which ejects the matter around them at a speed of more than 99% of the speed of light. A paper has been published reporting that a gigantic jet measuring 23 million light years in length has been observed in a faraway galaxy.

Black hole jets on the scale of the cosmic web | Nature
https://www.nature.com/articles/s41586-024-07879-y

Astronomers discover biggest ever seen black hole jets, which blast hot plasma well beyond their own host galaxy
https://phys.org/news/2024-09-astronomers-biggest-black-hole-jets.html

The research team named the jet ' Porpyrion ,' after a giant in Greek mythology.

Another giant from Greek mythology , Alcyoneus , is the name of a jet spewing from a galaxy about 3 billion light years away. Alcyoneus is the size of 100 Milky Way galaxies and was thought to be the largest jet ever observed. However, the newly discovered Porphyrion is even larger than Alcyoneus, with a size of 7 megaparsecs (about 23 million light years), which is equivalent to the length of 140 Milky Way galaxies lined up.

Porpyrion's jet was discovered by the European LOFAR (Low Frequency Array) radio telescope. The image below shows Porpyrion as seen by the LOFAR electronic telescope.

To identify the galaxy that emits the porpyllions, the research team also used data from the GMRT telescope in India, the DESI project, and the Keck Observatory in Hawaii. As a result, it was revealed that the porpyllions originate from a massive galaxy 7.5 billion light years away from Earth, with a mass about 10 times that of the Milky Way. Since they are emitted from a galaxy 7.5 billion light years away, the porpyllions observed today were emitted when the universe was much younger than it is now.

It is believed that 7.5 billion years ago, the network of galaxies known as the 'cosmic web' was more closely connected than it is today, so giant jets like Porphyrion could have influenced a much larger area of the cosmic web than they do today.

The research team pointed out that the LOFAR radio telescope only covers about 15% of the universe, suggesting that there may be multiple giant jets in the universe farther away than Porpyrion. 'We may only be seeing the tip of the iceberg,' said Martijn Oei of California Institute of Technology, one of the research team.

The research team says they would like to investigate in future how these giant jets affect the environment around them, particularly the extent to which they extend magnetic fields into space.