Pisces-I dwarf galaxy

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Galaxy
Pisces-I dwarf galaxy
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AladinLite
Constellation fishes
Position
equinox :  J2000.0 , epoch : J2000.0
Right ascension 01 h 03 m 56.6 s
declination 21 ° 53 ′ 41 ″
Appearance
Morphological type dSph / dIrr  
Angular expansion 1 °
Physical data
Affiliation Local group  
Radial velocity −75 km / s  
distance 260,000 ly /
80,000 pc
history
Discovery date 2009
Catalog names
PGC  3792 • Pisces I

The Pisces I dwarf galaxy (also Pisces I for short ) is a dwarf galaxy in the constellation Pisces ( lat. Pisces ) that is decaying. It can still be seen as an overfrequency in the galactic halo . It was in 2009, after analyzing the distribution of RR Lyrae stars in the screening of the Sloan Digital Sky Survey discovered.

Pices I is one of the faintest satellites in our Milky Way . Its mass is difficult to estimate because it does not correlate with the velocity dispersion . A value of around 10 5 M ☉ is given.

The galaxy is at a distance of 80  k pc from our solar system and is moving towards it at a speed of 75  km / s .

The large extension of about 1 ° on the one hand and the irregular shape on the other hand show that Pisces I is in the transition from a gravitationally bound to a gravitationally unbound system.

Pisces I is located near the plane of the Magellanic Clouds . There may be a physical connection between Pisces I and the Magellanic Current .

Individual evidence

  1. ↑ Igor D. Karachentsev, Valentina E. Karachentseva, Walter K. Huchtmeier, Dmitry I. Makarov: A Catalog of Neighboring Galaxies . In: The Astronomical Journal . 127, No. 4, April 2004, pp. 2031-2068. bibcode : 2004AJ .... 127.2031K . doi : 10.1086 / 382905 .
  2. ↑ a b c d Juna A. Kollmeier, Andrew Gould, Stephen Shectman, Ian B. Thompson, George W. Preston, Joshua D. Simon, Jeffrey D. Crane, Željko Ivezić u. a .: Spectroscopic Confirmation of the Pisces Overdensity . In: The Astrophysical Journal Letters . 705, No. 2, 2009, pp. L158-L162. arxiv : 0908.1381 . bibcode : 2009ApJ ... 705L.158K . doi : 10.1088 / 0004-637X / 705/2 / L158 .
  3. ↑ a b c d L. L. Watkins, NW Evans, V. Belokurov, MC Smith, PC Hewett, DM Bramich, GF Gilmore, MJ Irwin and others. a .: Substructure revealed by RR Lyraes in SDSS Stripe 82 . In: Monthly Notices of the Royal Astronomical Society . 398, No. 4, 2009, pp. 1757-70. arxiv : 0906.0498 . bibcode : 2009MNRAS.398.1757W . doi : 10.1111 / j.1365-2966.2009.15242.x .
  4. ↑ a b c V. Belokurov, MG Walker, NW Evans, G. Gilmore, MJ Irwin, D. Just, S. Koposov, M. Mateo and others. a .: Big fish, small fish: Two New Ultra-Faint Satellites of the Milky Way . In: The Astrophysical Journal Letters . 712, 2010, pp. L103-106. arxiv : 1002.0504 . bibcode : 2010ApJ ... 712L.103B . doi : 10.1088 / 2041-8205 / 712/1 / L103 .
  5. ↑ SIMBAD Astronomical Database . In: Results for Pisces I . Retrieved February 13, 2010.