Final answer:
An active galaxy is a type of galaxy that emits tremendous radiation, often due to a supermassive black hole at its center.
Step-by-step explanation:
The type of galaxy that emits tremendous radiation is known as an active galaxy. This category includes galaxies that are extremely luminous across the entire electromagnetic spectrum, often due to the presence of a supermassive black hole at their center, which accretes matter and emits high levels of energy.
Active galaxies stand out compared to typical spiral galaxies, which contain a mix of old and young stars and relatively more interstellar matter, or elliptical galaxies, which are dominated by old stars and contain little interstellar matter. Irregular galaxies also do not match the description of highly radiant galaxies as they are typically less massive, less luminous, and show disorganized structures.