Ask AI: please explain why we are selecting active galaxies if we use mid Infrared to do the sample selection

Active galaxies are the most luminous objects in the Universe, and they emit light across the entire electromagnetic spectrum, including in the mid-infrared range. In particular, the mid-infrared band is useful for detecting the warm dust clouds that surround the supermassive black holes at the center of active galaxies. These clouds of dust are heated up by the intense radiation emitted by the black hole, causing them to emit mid-infrared light. Therefore, by looking for mid-infrared emission, we can identify active galaxies and use them to study the properties of supermassive black holes, the accretion processes that fuel them, and the galactic environments in which they reside. Additionally, active galaxies are important for understanding galaxy evolution and the formation of large-scale structures in the Universe, making them a valuable scientific target for astronomers.