Pisces I (dwarf galaxy)

Pisces I Dwarf Galaxy
Observation data (J2000 epoch)
Constellation	Pisces
Right ascension	01h 03m 56.6s[1]
Declination	+21° 53′ 41″[1]
Distance	260 kly (80 kpc)[2]
Absolute magnitude (V)	−10.35[3]
Characteristics
Type	dIrr/dSph[3]
Apparent size (V)	~1°[4]
Other designations
	Pisces Overdensity,[2] Psc I,[5] PGC 3792,[6] LEDA 3792[5]

Pisces I (Psc I) or Pisces Overdensity is a clump of stars in the Milky Way's halo, which may be a disrupted dwarf spheroidal galaxy.[7] It is situated in the Pisces constellation and was discovered in 2009 by analysis of distribution of RR Lyrae stars in the data obtained by the Sloan Digital Sky Survey's data.[2] The galaxy is located at the distance of about 80 kpc from the Sun and moves towards it with a speed of about 75 km/s.[4]

Pisces I is one of the faintest satellites of the Milky Way.[7] Its mass is estimated to be at least 10⁵ Solar masses.[2] However it has a large size of about several degrees (around 1 kpc) and may be in a transitional phase between a gravitationally bound galaxy and completely unbound system.[4] Pisces I is located near the plane, where the Magellanic Clouds lie. There may exist a connection between the Magellanic stream and this galaxy.[2]

References

Karachentsev ID, et al. (2004). "A Catalog of Neighboring Galaxies". Astronomical Journal. 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905.
Watkins, L. L.; et al. (2009), "Substructure revealed by RR Lyraes in SDSS Stripe 82", Monthly Notices of the Royal Astronomical Society, 398 (4): 1757–70, arXiv:0906.0498, Bibcode:2009MNRAS.398.1757W, doi:10.1111/j.1365-2966.2009.15242.x.
Boyer, Martha L; Skillman, Evan D; Van Loon, Jacco Th; Gehrz, Robert D; Woodward, Charles E (2009). "Aspitzerstudy of Asymptotic Giant Branch Stars. Iii. Dust Production and Gas Return in Local Group Dwarf Irregular Galaxies". The Astrophysical Journal. 697 (2): 1993. arXiv:0903.3871. Bibcode:2009ApJ...697.1993B. doi:10.1088/0004-637X/697/2/1993.
Kollmeier, Juna A.; et al. (2009), "Spectroscopic Confirmation of the Pisces Overdensity", The Astrophysical Journal Letters, 705 (2): L158–L162, arXiv:0908.1381, Bibcode:2009ApJ...705L.158K, doi:10.1088/0004-637X/705/2/L158.
"NAME Pisces I". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 March 2018.
"Object No. 1 - Pisces I". NASA/IPAC Extragalactic Database.
Belokurov, V.; et al. (2010), "Big fish, small fish: Two New Ultra-Faint Satellites of the Milky Way", The Astrophysical Journal Letters, 712: L103–106, arXiv:1002.0504, Bibcode:2010ApJ...712L.103B, doi:10.1088/2041-8205/712/1/L103.

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[Karachentsev2004-1] Karachentsev ID, et al. (2004). "A Catalog of Neighboring Galaxies". Astronomical Journal. 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905.

[Watkins2009-2] Watkins, L. L.; et al. (2009), "Substructure revealed by RR Lyraes in SDSS Stripe 82", Monthly Notices of the Royal Astronomical Society, 398 (4): 1757–70, arXiv:0906.0498, Bibcode:2009MNRAS.398.1757W, doi:10.1111/j.1365-2966.2009.15242.x.

[Boyer2009-3] Boyer, Martha L; Skillman, Evan D; Van Loon, Jacco Th; Gehrz, Robert D; Woodward, Charles E (2009). "Aspitzerstudy of Asymptotic Giant Branch Stars. Iii. Dust Production and Gas Return in Local Group Dwarf Irregular Galaxies". The Astrophysical Journal. 697 (2): 1993. arXiv:0903.3871. Bibcode:2009ApJ...697.1993B. doi:10.1088/0004-637X/697/2/1993.

[Kollmeier2009-4] Kollmeier, Juna A.; et al. (2009), "Spectroscopic Confirmation of the Pisces Overdensity", The Astrophysical Journal Letters, 705 (2): L158–L162, arXiv:0908.1381, Bibcode:2009ApJ...705L.158K, doi:10.1088/0004-637X/705/2/L158.

[SIMBAD-5] "NAME Pisces I". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 March 2018.

[NED-6] "Object No. 1 - Pisces I". NASA/IPAC Extragalactic Database.

[Belokurov2010-7] Belokurov, V.; et al. (2010), "Big fish, small fish: Two New Ultra-Faint Satellites of the Milky Way", The Astrophysical Journal Letters, 712: L103–106, arXiv:1002.0504, Bibcode:2010ApJ...712L.103B, doi:10.1088/2041-8205/712/1/L103.