Starburst Galaxy

Galaxies observed to be forming stars at an unusually fast rate (about 103 times greater than in a normal galaxy). At such high levels of star formation, the supply of gas and dust within the galaxy would be exhausted within about 108 years. This indicates that these episodes of intense star formation started relatively recently and perforce will end relatively soon.
The areas of high formation rates may be spread throughout a galaxy, but most starbursts are observed in a small region around the nucleus. Star formation is probably triggered by tidal interactions during galactic encounters, galactic mergers, or due to the presence of a galactic bar, all of which result in the accumulation of substantial amounts of gas and dust in the central regions of the galaxy. Massive stars form from the available enshrouding gas and dust, which emit large amounts of UV radiation. This radiation is absorbed by the surrounding dust and reemitted at IR wavelengths, making starburst galaxies among the most luminous IR objects in the Universe. Supernova explosions and stellar winds from the massive stars eventually sweep the gas from the galaxy and halt further star formation. Starburst galaxies appear to be more prevalent in the early universe than they are now. These galaxies, ~12 billion light years distant, appear to have characteristics similar to nearby starbursts and indicate that galaxy interactions were much more common in the past.


Image source: http://hubblesite.org/gallery/album/entire/pr1997034d/web/.