These are called Seyfert galaxies . Luminosity of the nucleus is more comparable to the brightness of the rest of the galaxy, so the host galaxy is easier to see and study. Since they're closer, we can also see more details. However, these active regions are so small that even the best telescopes can't resolve the centers. All the radiation, high energy particles, etc. are coming from an area about the size of our Solar System.
Some galaxies are very bright in radio waves compared to normal galaxies.
When these radio galaxies are mapped, we see most of the emission is coming from radio lobes that look like larger versions of the bipolar flows from young stars or in the formation of planetary nebulae. So radio galaxies and active galactic nuclei are tied together. Radio maps gave us the details, also images from large optical telescopes show more details. Tiny core, two jets shooting off in opposite directions, two large lobes of radio emission. Some quasars have the same structure as radio galaxies.