A Luminous Infrared Galaxy (LIRG) is a type of galaxy that emits a significant amount of its energy in the infrared spectrum. These galaxies are typically more than 10 times as luminous as normal galaxies, often due to intense star formation and active galactic nuclei. The infrared light is primarily produced by dust that absorbs ultraviolet and visible light from stars and re-emits it as infrared radiation. LIRGs are often found in regions of high galaxy density, such as galaxy clusters, and can be indicators of galaxy mergers or interactions. They are important for understanding the processes of star formation and galaxy evolution. Examples of LIRGs include the Antennas Galaxies and NGC 6240.