IRREGULAR GALAXY

 

Irregular Galaxies

Irregular galaxies have no definite shape, though they are in constant motion like all other galaxies. They have a chaotic appearance as they don’t seem to possess a nuclear bulge or traces of spiral arms.

Some irregular galaxies were once spiral or elliptical galaxies but were deformed by an uneven external gravitational force. Irregular galaxies may contain abundant amounts of gas and dust Irregular galaxies are commonly small, about one-tenth the mass of the Milky Way galaxy.

Until now, three major types of irregular galaxies have been established:

1. Irr I – they feature some structure but not enough to be placed into the Hubble sequence.
2. Irr II – they do not appear to feature any structure.
3. DIrr III – dwarf irregular galaxy. They tend to have low metallicity and relatively high levels of gas. They are also believed to be similar to the earliest galaxies that populated the Universe.

Irregular galaxies can be distorted by the gravity of a larger neighbor, a good example of this are the Large and Small Magellanic Clouds, distorted by our Milky Way.

HARINI. E (2213721033010)