agn-feedback

Active galactic nuclei are galaxy cores lit up by supermassive black holes pulling in gas. Quasars, Seyfert galaxies, radio galaxies, and blazars are largely one machine seen from different angles and at different power.

Galaxies are not static objects. They grow, merge, transform, and eventually fall quiet. Over 13.8 billion years the universe has gone from small, chaotic protogalaxies to the spirals and giant ellipticals we see today, and tracing that transformation is one of astronomy's deepest challenges.