Pisces Dwarf
{{about|the suspected satellite galaxy of the Triangulum Galaxy|other dwarf galaxies labelled Pisces|Pisces (disambiguation)}}
{{Infobox Galaxy
| name = Pisces Dwarf
| image = LGS 3 ubv.jpg
| image_size = 250px
| caption= The Pisces Dwarf in combined UV and visible light
| epoch = J2000
| type = dIrr/dSph{{cite web
| title=NASA/IPAC Extragalactic Database
| work=Results for Pisces Dwarf
| url=http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=Pisces+Dwarf#ObjNo1
| access-date=2007-03-15 }}
| dist_ly = 2.51 ± 0.08 Mly (769 ± 25 kpc)
| z = -287 ± 0 km/s
| constellation name = Pisces
| names = Pisces I, Psc I, LGS 3, PGC 3792, LEDA 3792
}}
The Pisces Dwarf, also known as Pisces I, 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.{{cite journal
| author=McConnachie, A. W.
| author2=Irwin, M. J.
| author3=Ferguson, A. M. N.
| author4=Ibata, R. A.
| author5=Lewis, G. F.
| author6=Tanvir, N.
| title=Distances and metallicities for 17 Local Group galaxies
| journal=Monthly Notices of the Royal Astronomical Society
| date=2005
| volume=356
| issue=4
| pages=979–997
| bibcode=2005MNRAS.356..979M
| doi=10.1111/j.1365-2966.2004.08514.x | doi-access=free
|arxiv = astro-ph/0410489 }}
History
It was discovered by Valentina Karachentseva in 1976.{{cite journal
| author=Karachentseva, V. E.
| title=Some characteristics of isolated pairs composed of a normal galaxy and DDO-dwarf
| journal=Soobshch. Spets. Astrofiz. Obs.
| volume=18
| date=1976
| issue=18
| pages=42–51
| bibcode=1976SoSAO..18...42K
| url=https://books.google.com/books?id=A20hAAAAMAAJ&q=%D0%BA%D0%B0%D1%80%D0%B0%D1%87%D0%B5%D0%BD%D1%86%D0%B5%D0%B2%D0%B0+%22%D1%85%D0%B0%D1%80%D0%B0%D0%BA%D1%82%D0%B5%D1%80%D0%B8%D1%81%D1%82%D0%B8%D0%BA%D0%B8+%D0%B8%D0%B7%D0%BE%D0%BB%D0%B8%D1%80%D0%BE%D0%B2%D0%B0%D0%BD%D0%BD%D1%8B%D1%85%22 }}{{cite journal|doi=10.1088/0004-637X/730/1/14|title=The Acs Lcid Project. V. The Star Formation History of the Dwarf Galaxy Lgs-3: Clues to Cosmic Reionization and Feedback|journal=The Astrophysical Journal|volume=730|issue=1|pages=14|year=2011|last1=Hidalgo|first1=Sebastian L.|last2=Aparicio|first2=Antonio|last3=Skillman|first3=Evan|last4=Monelli|first4=Matteo|last5=Gallart|first5=Carme|last6=Cole|first6=Andrew|last7=Dolphin|first7=Andrew|last8=Weisz|first8=Daniel|last9=Bernard|first9=Edouard J.|last10=Cassisi|first10=Santi|last11=Mayer|first11=Lucio|last12=Stetson|first12=Peter|last13=Tolstoy|first13=Eline|last14=Ferguson|first14=Henry|arxiv = 1101.5762 |bibcode = 2011ApJ...730...14H |s2cid=118411768}}
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.{{cite journal |author=Miller, B. W., Dolphin, A. E., Lee, M. G., Kim, S. C., Hodge, P. |title=The Star Formation History of LGS3 |journal=The Astrophysical Journal |volume=562 |issue=2 |pages=713–726 |doi=10.1086/323853 |arxiv = astro-ph/0108408 |bibcode = 2001ApJ...562..713M |year=2001 |s2cid=119089499 }}
References
{{reflist}}
External links
- {{commonscat-inline}}
{{Sky|01|03|55.0|+|21|53|06|2510000}}
{{Triangulum Galaxy}}
Category:Dwarf irregular galaxies
Category:Dwarf spheroidal galaxies