What are luminous infrared galaxies? How do they differ from other galaxies?

Luminous infrared galaxies, or LIRGs, are a type of galaxy that emits a large amount of infrared radiation. This radiation is produced by the intense star formation and black hole activity taking place within these galaxies. LIRGs are typically characterized by their high levels of dust, gas, and stars, which fuel the intense activity that takes place within them.

            One key way that LIRGs differ from other galaxies is in their level of star formation. LIRGs are among the most prolific star-forming galaxies in the universe, and they often have hundreds or thousands of times more star formation than typical spiral galaxies like our own Milky Way. This intense star formation is driven by the large amounts of gas and dust present within LIRGs, which provide the raw materials needed for new stars to form.

Another way that LIRGs differ from other galaxies is in their level of black hole activity. Many LIRGs contain active galactic nuclei, or AGN, which are supermassive black holes located at the center of the galaxy. These black holes can be millions or billions of times more massive than the sun, and they can emit powerful jets of radiation as they consume matter. The presence of AGN in LIRGs can contribute to the high levels of infrared radiation that these galaxies emit.

LIRGs also differ from other galaxies in their overall appearance and structure. Many LIRGs are characterized by their irregular or asymmetrical shapes, which can be caused by interactions with other galaxies or by the intense gravitational forces at work within the galaxy. In contrast, other types of galaxies, such as spiral galaxies, tend to have more regular and symmetrical shapes.

In conclusion, luminous infrared galaxies, or LIRGs, are a type of galaxy that emit a large amount of infrared radiation due to their high levels of star formation and black hole activity. They differ from other galaxies in their level of star formation, black hole activity, and overall appearance and structure, making them unique and interesting objects to study.