Researchers Observe Largest Black Hole Jets Ever Discovered

The supermassive black holes at the center of galaxies aren’t just decorations. The intense radiation they emit as they feed helps to blow away gas and dust that would otherwise form stars, providing feedback that limits a galaxy’s growth. But their influence can extend far beyond the galaxy they inhabit. Many black holes produce jets, and in the case of supermassive black holes, these jets can blast material entirely out of the galaxy.

Now, researchers are getting a clearer picture of just how far these jets can travel beyond the galaxy. A new study describes the largest jets ever observed, spanning a total distance of 23 million light-years (seven megaparsecs). At these distances, jets could easily send material to other galaxies and through the cosmic dark matter web that makes up the universe.

extreme jet planes

Jets form in the complex environment near a black hole. The intense heating of incoming material ionizes and heats it, creating electromagnetic fields that act as natural particle accelerators. This creates jets of particles traveling at a large fraction of the speed of light. These will eventually collide with nearby material, creating shock waves that heat and accelerate it as well. Over time, this results in large-scale, coordinated outflows of material, with the size of the jet proportional to a combination of the size of the black hole and the amount of material it feeds on.

Black holes typically form jets at each of their poles, creating dual jets that move in opposite directions. We’ve seen many examples of this at different scales, from stellar-mass black holes all the way up to supermassive black holes, which can form quasars, the brightest objects in the universe.

The discovery of the new jets came from a systematic search for large jets, conducted at radio wavelengths at an observatory called LOFAR (Low Frequency Array) that covers parts of the Northern Hemisphere sky. Data obtained with this telescope was scoured through a combination of machine learning and citizen scientist volunteers. The program identified more than 11,000 jets spanning megaparsecs (each parsec is just over 3 light-years). The paper released Wednesday describes the largest of these jets, which has been named Porphyrion after a giant from Greek mythology.

Initial follow-up observations included finding the galaxy that produced the phenomenon. There were two objects in roughly the right place, but one had lobes extending along the axis of the jets, suggesting that it was the most likely source. The galaxy is about ten times as massive as the Milky Way, and spectroscopic analyses suggest we are looking at it as it existed roughly six billion years after the Big Bang, or just over half the time before the present day.