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Pisces Dwarf

Coordinates: Sky map 01h 03m 55.0s, +21° 53′ 06″
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Pisces Dwarf
Hubble Space Telescope image of the Pisces Dwarf
Observation data (J2000 epoch)
ConstellationPisces
Right ascension01h 03m 55.0s[1]
Declination+21° 53′ 06″[1]
Redshift-287 ± 0 km/s[1]
Distance2.51 ± 0.08 Mly (769 ± 25 kpc)[2]
Apparent magnitude (V)14.2[1]
Characteristics
TypedIrr/dSph[1]
Apparent size (V)2′ × 2′[1]
Other designations
Pisces I, Psc I, LGS 3,[1] PGC 3792,[1] LEDA 3792

The Pisces Dwarf, also known as Pisces I (Psc I) or LGS3,[1] is an irregular dwarf galaxy and suspected satellite galaxy of the Triangulum Galaxy (M33), located within the constellation Pisces.[2] Discovered by astronomer Valentina Karachentseva in 1976, it is approaching the Milky Way at 287 km/s, evident by its blueshift, and may be a galaxy currently transitioning between a dwarf spheroidal and dwarf irregular galaxy;[3] alternatively, it may be a rare unique version of one of the two types.[2]

Structure

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The Pisces Dwarf has a very irregular shape, and is composed primarily of moderately aged and young stars, as given by its metallicity of [Fe/H]=−2.10 ± 0.22.[2] Its star formation has declined, with its peak starburst period suspected to be an estimated 8 billion years ago,[4] and a significant lack of new star formation within the past 100 million years.[2][5] It is suspected to be a potential transition galaxy, currently transitioning from a dwarf irregular to a dwarf spheroidal galaxy.[5][6]

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References

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  1. 1 2 3 4 5 6 7 8 9 "NASA/IPAC Extragalactic Database". Results for Pisces Dwarf. Retrieved 2007-03-15.
  2. 1 2 3 4 5 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. ↑ Garofalo, Alessia; Tantalo, Maria; Cusano, Felice; Clementini, Gisella; Calura, Francesco; Muraveva, Tatiana; Paris, Diego; Speziali, Roberto (2021-07-01). "Born in a Pair (?): Pisces II and Pegasus III*". The Astrophysical Journal. 916 (1): 10. arXiv:2105.11488. Bibcode:2021ApJ...916...10G. doi:10.3847/1538-4357/ac0253. ISSN 0004-637X.
  4. ↑ Karachentseva, V. E. (1976). "Some characteristics of isolated pairs composed of a normal galaxy and DDO-dwarf". Soobshch. Spets. Astrofiz. Obs. 18 (18): 42–51. Bibcode:1976SoSAO..18...42K.
  5. 1 2 Miller, B. W., Dolphin, A. E., Lee, M. G., Kim, S. C., Hodge, P. (2001). "The Star Formation History of LGS3". The Astrophysical Journal. 562 (2): 713–726. arXiv:astro-ph/0108408. Bibcode:2001ApJ...562..713M. doi:10.1086/323853. S2CID 119089499.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ↑ Hidalgo, Sebastian L.; Aparicio, Antonio; Skillman, Evan; Monelli, Matteo; Gallart, Carme; Cole, Andrew; Dolphin, Andrew; Weisz, Daniel; Bernard, Edouard J.; Cassisi, Santi; Mayer, Lucio; Stetson, Peter; Tolstoy, Eline; Ferguson, Henry (2011). "The Acs Lcid Project. V. The Star Formation History of the Dwarf Galaxy Lgs-3: Clues to Cosmic Reionization and Feedback". The Astrophysical Journal. 730 (1): 14. arXiv:1101.5762. Bibcode:2011ApJ...730...14H. doi:10.1088/0004-637X/730/1/14. S2CID 118411768.
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