Irregular Galaxies


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Related to Irregular Galaxies: Elliptical Galaxies, Spiral Galaxies

Irregular Galaxies

 

stellar systems that are distinguished from spiral or elliptical galaxies by their lack of orderly structure and their patchy shape. Sometimes irregular galaxies that are amorphous and have no clear form are encountered. These consist of stars and dust, whereas the majority of irregular galaxies also contain gas and a large number of very bright, hot blue giants. Clusters of the latter create the appearance of patchiness. There are irregular galaxies that have traces of spiral structure, in particular, the stellar systems closest to our galaxy, the Magellanic Clouds. Only a small number of galaxies are irregular.

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Previous studies have shown that the more distant dwarf irregular galaxies have large reservoirs of neutral hydrogen gas, the fuel for star formation.
Milky Way Ransacks Nearby Dwarf Galaxies
The small irregular galaxies were born about 100 million years before reionization began and had just started to churn out stars.
Hubble solves mystery of ghost galaxies
In addition, recent work by Erik Tollerud (University of California, Irvine) and his colleagues show that the Clouds are much bluer and younger than comparably sized irregular galaxies, and they form stars at a much higher rate.
The great galactic travelers: new observations suggest that the Magellanic Clouds--for decades considered satellites of the Milky Way--have taken an unexpected path
Most are spiral and irregular galaxies of normal mass, and more than 30 percent are colliding.
X-ray survey reveals differences between near and far galaxies
But they also arise in dwarf and irregular galaxies, and they surge forth in bursts of activity when galaxies collide.
Stellar origins: from the cold depths of space
Ellipticals include both the biggest and smallest galaxies in the universe, and they differ from spirals and irregular galaxies because almost all their stars are very old.
Smoking supernovae dusty galaxies
Nothing in my notes, however, suggests that one of these irregular galaxies is more difficult to observe than the other, so the selection must have been arbitrary.
Observing Faint Nearby Galaxies
The Magellanic-type irregular galaxies are defined as having no nucleus at all: whereas ellipticals are "all bulge," Magellanic irregulars are "all disk.
Exploring the Hubble Sequence by Eye : Trained eyes and clear, dark skies can open up a new dimension in deep-sky observing
It is nearly invisible in the elliptical galaxies that have only old stars but practically all you see in irregular galaxies like the Magellanic Clouds.
Meet the Milky Way
Type Ib, Ic, and II supernovae are always found in spiral or irregular galaxies, usually in spiral arms and near ionized-hydrogen (H II) regions, sites of active star formation.
A supernova with an identity crisis

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