Pisces I (dwarf galaxy)
Pisces I or Pisces overdensity is a clump of stars in the Milky Way's halo, which may be a disrupted dwarf spheroidal galaxy.[1] 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 Sloan Digital Sky Survey's data.[3] 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.[2]
Pisces I is one of the faintest satellites of the Milky Way.[1] Its mass is estimated to be at least 105 Solar masses.[3] 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.[2] Pisces I is located near the plane, where Magellanic Clouds lie. There may exist a connection between the Magellanic stream this galaxy.[3]
References
- ^ a b c d Belokurov, V.; Walker, M. G.; Evans, N. W. 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.
- ^ a b c d e Kollmeier, Juna A.; Gould, Andrew; Shectman, Stephen 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.
- ^ a b c d Watkins, L.L.; Evans, N. W.; Belokurov, V. 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.