Magellanic spiral

Magellanic spiral galaxies are (usually) dwarf galaxies which are classified as the type Sm (and SAm, SBm, SABm). They are galaxies with one single spiral arm, and are named after their prototype, the Large Magellanic Cloud, an SBm galaxy. They can be considered to be intermediate between dwarf spiral galaxies and irregular galaxies.

Magellanic spirals

SAm galaxies are a type of unbarred spiral galaxy, while SBm are a type of barred spiral galaxy.^[1] SABm are a type of intermediate spiral galaxy.

Type Sm and Im galaxies have also been categorized as irregular galaxies with some structure (type Irr-1). Sm galaxies are typically disrupted and asymmetric.^[2] dSm galaxies are dwarf spiral galaxies or dwarf irregular galaxies, depending on categorization scheme.

The Magellanic spiral classification was introduced by Gerard de Vaucouleurs, along with Magellanic irregular (Im), when he revamped the Hubble classification of galaxies.

Grades

Magellanic Spiral Galaxies

Magellanic Spirals Example Type Image Information Notes SAdm SAm SABdm SABm SBdm Large Magellanic Cloud SBm A satellite of the Milky Way, and the prototype galaxy for the Magellanic Spiral class Sdm Sm	Dwarf Magellanic Spirals Example Type Image Information Notes dSAdm dSAm dSABdm dSABm dSBdm dSBm dSdm dSm

List of Magellanic spirals

Barred (SBm)

• Large Magellanic Cloud (LMC [prototype])
• Small Magellanic Cloud (SMC)
• NGC 1311 ^[3]
• NGC 4618 ^[4]
• NGC 4236
• NGC 55
• NGC 4214
• NGC 3109

Intermediate (SABm)

• NGC 4625
• NGC 5713

Unbarred (SAm)

• NGC 5204^[5]
• NGC 2552

See also

• Galaxy morphological classification

References

1. Linda S. Sparke, John Sill Gallagher, "Galaxies in the Universe: An Introduction", 2ed., Cambridge University Press, '2007', ISBN 978-0-521-85593-8
2. citeBase; Neutral Hydrogen in the Interacting Magellanic Spirals NGC 4618/4625; Stephanie J. Bush; Eric M. Wilcots; (accessed 1 March 2009)
3. Paul B. Eskridge; "Recent Star and Cluster Formation in the Nearby Magellanic Spiral NGC 1311"; 'American Astronomical Society Meeting' 208, #14.04; Bulletin of the American Astronomical Society, Vol. 38, p.93; (accessed 1 March 2009)
4. University of Wisconsin, BARRED MAGELLANIC SPIRALS (accessed 1 March 2009)
5. NASA/IPAC Extragalactic Database