Active Galactic Nuclei: The Powerhouses of Galaxies

An active galactic nucleus (AGN) is a galaxy’s central region where a supermassive black hole feeds.
As matter spirals in, it releases enormous energy—outshining the galaxy’s stars.
AGN can emit light across the entire electromagnetic spectrum, from radio waves to gamma rays.
Quasars, blazars, and Seyfert galaxies are all different types of AGN.
The energy comes from accretion disks of gas heated to millions of degrees.
Some AGN shoot out colossal jets that stretch millions of light-years.
Their brightness can vary quickly, showing how compact and extreme their cores are.
AGN were most common billions of years ago, when galaxies and black holes were young.
They play a role in galaxy evolution, regulating star formation with their powerful outflows.
Studying AGN helps astronomers probe the physics of black holes and the early universe.