Pisces Dwarf

This article is about the suspected satellite galaxy of the Triangulum Galaxy. For other dwarf galaxies labelled Pisces, see Pisces (disambiguation).
Pisces Dwarf
Observation data (J2000 epoch)
Constellation Pisces
Right ascension 01h 03m 55.0s[1]
Declination +21° 53′ 06″[1]
Redshift -287 ± 0 km/s[1]
Distance 2.51 ± 0.08 Mly (769 ± 25 kpc)[2]
Apparent magnitude (V) 14.2[1]
Characteristics
Type dIrr/dSph[1]
Apparent size (V) 2′ × 2′[1]
Other designations
LGS 3,[1] PGC 3792[1]

Pisces Dwarf is an irregular dwarf galaxy that is part of the Local Group. The galaxy, taking its name from the constellation Pisces where it appears, is suspected of being a satellite galaxy of the Triangulum Galaxy (M33). It displays a blueshift, as it is approaching the Milky Way at 287 km/s. It may be transition-type galaxy, somewhere between dwarf spheroidal and dwarf irregular. Alternatively, it may be a rare, but statistically acceptable, version of one of the two types.[2]

History

It was discovered by Valentina Karachentseva in 1976.[2][3][4]

Star formation history

Apparently, the star formation rate in the Pisces Dwarf has been declining for the past 10 billion years. Most of the galaxy's stars were formed in its early years, about 8 billion years ago. The study has also shown that there has been no significant star formation for the past 100 million years. Hence, most of the stars that populate this galaxy are old, metal-rich stars aged about 2.5 billion years. However, there are small clusters of young, hot, blue stars on the outer areas of the galaxy.[5]

References

  1. 1 2 3 4 5 6 7 8 "NASA/IPAC Extragalactic Database". Results for Pisces Dwarf. Retrieved 2007-03-15.
  2. 1 2 3 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/0410489Freely accessible. Bibcode:2005MNRAS.356..979M. doi:10.1111/j.1365-2966.2004.08514.x.
  3. ↑ 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.
  4. ↑ 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: 14. arXiv:1101.5762Freely accessible. Bibcode:2011ApJ...730...14H. doi:10.1088/0004-637X/730/1/14.
  5. ↑ 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/0108408Freely accessible. Bibcode:2001ApJ...562..713M. doi:10.1086/323853.

Coordinates: 01h 03m 55.0s, +21° 53′ 06″

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