AGN stands for active galactic nuclei, which are extremely luminous and energetic regions at the centers of galaxies. AGN are powered by accretion of material onto a supermassive black hole, which releases large amounts of energy in the form of radiation across the electromagnetic spectrum. Studying AGN is important for understanding the processes that drive galaxy evolution and the growth of supermassive black holes. Researchers study AGN using a variety of observational techniques, such as multi-wavelength surveys, spectroscopy, and theoretical models.