Stars evolve - and so do galaxies.
Comparison between observations and models of evolving stellar populations helps understand the star formation process, triggering mechanisms, influence of the environment, the chemical history, and processes in the interstellar gas. The star formation rate in these galaxies is about 10 to 50 times higher than the star formation rate in normal spiral galaxies. Interactions with other galaxies or mergers can trigger the enhancement of the star formation activity in galaxies leading to a starburst. The young and massive stars in the starburst galaxies emit a large amount of energy in the ultraviolet. A part of this energy is absorbed by the surrounding dust and reradiated in the farinfrared.