Pegasus Dwarf Irregular Galaxy

The Pegasus Dwarf Irregular Galaxy (also known as Peg DIG or the Pegasus Dwarf) is a dwarf irregular galaxy in the direction of the constellation Pegasus. It was discovered by A. G. Wilson in the 1950s. The Pegasus Dwarf is a companion of the Andromeda Galaxy in the Local Group.

Pegasus Dwarf Irregular Galaxy
Pegasus Dwarf Irregular Galaxy (Pegasus Dwarf), DDO 216, UGC12613
Observation data (J2000 epoch)
Constellation	Pegasus
Right ascension	23h 28m 36.2s[1]
Declination	+14° 44′ 35″[1]
Redshift	−183 ± 0 km/s[1]
Distance	3.0 ± 0.1 Mly (920 ± 30 kpc)[2]
Apparent magnitude (V)	13.2[1]
Characteristics
Type	dIrr/dSph[1][a]
Apparent size (V)	5.0′ × 2.7′[1]
Other designations
UGC 12613,[1] PGC 71538,[1] DDO 216,[1] Pegasus Dwarf,[1] PegDIG[1]

General information

In 1975 Tully & Fisher determined that it was part of the Local Group.^[3] The metallicity and the related distance estimate has been subject to discussions in the scientific literature, with varying results; however, recently, by use of the tip of the red-giant branch, a distance within 10% error was achieved in 2000^[4][5] and then improved to 3% in 2005.^[2]

Location of Pegasus Dwarf in the Local Group.

In popular culture

The science fiction television series Stargate Atlantis takes place in the "Pegasus galaxy" and has shown images of an irregular galaxy. However, the franchise has not explicitly stated if it is the Irregular, Spheroidal, or an entirely fictional location,^[6] but since the series claimed the Pegasus galaxy to be 3 million light years away, it is likely the irregular one.

See also

• Pegasus Dwarf Spheroidal Galaxy (Peg dSph)
• Pegasus galaxy, the Stargate Atlantis fictional location.

Notes

1. ^{^} NED gives the galaxy classification as both dIrr and dSph, which means that it is a transitory between dwarf irregular and dwarf spheroidal. It is noted as transitory in Cole et al. 1999.^[7]

References

1. "NASA/IPAC Extragalactic Database". Results for PegDIG. Retrieved 2007-03-15.
2. McConnachie, A. W.; Irwin, M. J.; Ferguson, A. M. N.; Ibata, R. A.; Lewis, G. F.; Tanvir, N. (2005). "Distances and metallicities for 17 Local Group galaxies". Monthly Notices of the Royal Astronomical Society. 356 (4): 979–997. arXiv:astro-ph/0410489. Bibcode:2005MNRAS.356..979M. doi:10.1111/j.1365-2966.2004.08514.x.
3. Gallager, J S.; Tolstoy, E.; Dohm-Palmer, Robbie C.; Skillman, E D.; Cole, A A.; Hoessel, J G.; Saha, A.; Mateo, M. (1998). "A Wide Field Planetary Camera 2 Study of the Resolved Stellar Population of the Pegasus Dwarf Irregular Galaxy (DDO 216)". The Astronomical Journal. 115 (5): 1869–1889. arXiv:astro-ph/9805284. Bibcode:1998AJ....115.1869G. doi:10.1086/300328. hdl:11370/9e84a3d9-98a1-45ad-9bab-3d703d3b0eba. S2CID 119497686.
4. Karachentsev, Igor D.; Karachentseva, Valentina E.; Huchtmeier, Walter K.; Makarov, Dmitry I. (2004). "A Catalog of Neighboring Galaxies". The Astronomical Journal. 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905.
5. van den Bergh, Sidney (2000). The Galaxies of the Local Group. Cambridge, UK: Cambridge University Press. Bibcode:2000glg..book.....V. ISBN 0-521-65181-6.
6. "The Return" (Stargate Atlantis)
7. Cole, Andrew A.; Tolstoy, Eline; Gallagher, John S., III; Hoessel, John G.; Mould, Jeremy R.; Holtzman, Jon A.; Saha, Abhijit; Ballester, Gilda E.; Burrows, Christopher J.; Clarke, John T.; Crisp, David; Griffiths, Richard E.; Grillmair, Carl J.; Hester, Jeff J.; Krist, John E.; Meadows, Vikki; Scowen, Paul A.; Stapelfeldt, Karl R.; Trauger, John T.; Watson, Alan M.; Westphal, James R. (1999). "Stellar Populations at the Center of IC 1613". The Astronomical Journal. 118 (4): 1657–1670. arXiv:astro-ph/9905350. Bibcode:1999AJ....118.1657C. doi:10.1086/301042. S2CID 17566586.{{cite journal}}: CS1 maint: multiple names: authors list (link)

External links

• Pegasus Dwarf Irregular Galaxy on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images