First Images of Particle Jets at Edge of a Supermassive Black Hole
First Images of Particle Jets at Edge of a Supermassive Black Hole
Supermassive black holes appear to occupy the center of almost all galaxies. When they are actively swallowing matter, these black holes can power energetic jets that shine brighter than the entire rest of the galaxy, and can shoot matter free of it. Despite the mass and energy involved, however, the origin of these jets has been extremely hard to image, both because they’re relatively compact, and because they’re situated in the crowded centers of distant galaxies.
Now, however, researchers are putting together an array of telescopes stretched across the globe with the specific goal of imaging the environment near these supermassive black holes. The team behind the Event Horizon Telescope has now used it to image the black hole at the center of the M87 galaxy, and returned the first details of the disk of matter that is being sucked into that galaxy’s central black hole.
It’s difficult to imagine the environment near a supermassive black hole. These objects are typically over a million times the mass of our Sun, but all of that matter is crammed into a space that may only be a fraction of the Sun’s radius. Any matter falling into one piles up into an orbiting disk of material (called an accretion disk) that increases in density and energy as you get closer to black hole. Any matter that crosses a critical point, however, rapidly spirals inward to the black hole itself. The inner area of the disk is so energetic that it actually sends matter away from the black hole in a wind of particles.
But that’s not the most energetic part. Even further inward, the intense magnetic field lines sometimes cross the event horizon of the black hole itself, propelling intense beams of charged particles away from the black hole. These jets interact with the wind of particles coming from the accretion disk, which focuses them into narrow beams that move at nearly the speed of light. These have so much energy that they are (in some cases) able to propel particles for hundreds of thousands of light years, sending them entirely out of the galaxy, where the particles eventually slow by interacting with the intergalactic medium.