Mice Galaxies

NGC 4676, or the Mice Galaxies, are two spiral galaxies in the constellation Coma Berenices. About 290 million light-years away,[2] they began the process of colliding and merging. Their name refers to the long tails produced by tidal action—the relative difference between gravitational pulls on the near and far parts of each galaxy—known here as a galactic tide. It is a possibility that both galaxies, which are members of the Coma cluster,[3] have experienced collision, and will continue colliding until they coalesce.

NGC 4676A / 4676B
The Mice Galaxies, NGC 4676A (right)/NGC 4676B (left)
Observation data (J2000 epoch)
ConstellationComa Berenices
Right ascension 12h 46m 10.1s /  12h 46m 11.2s[1]
Declination+30° 43′ 55″ / +30° 43′ 22″[1]
Redshift6613 ± 8 / 6607 ± 7 km/s[1]
Distance290 Mly (89 Mpc)[2]
Apparent magnitude (V)14.7 / 14.4[1]
Characteristics
TypeIrr / SB(s)0/a pec[1]
Size760,000 ly (233 kpc) (estimated)[lower-alpha 1]
Apparent size (V)2′.3 × 0′.7 / 2′.2 × 0′.8[1]
Notable featuresInteracting galaxies
Other designations
Mice Galaxies,[1] IC 819 / 820,[1] UGC 7938 / 7939,[1]
PGC 43062 / 43065,[1] Arp 242[1]

The colors of the galaxy are peculiar. In NGC 4676A a core with some dark markings is surrounded by a bluish white remnant of spiral arms. The tail is unusual, starting out blue and terminating in a more yellowish color, despite the fact that the beginning of each arm in virtually every spiral galaxy starts yellow and terminates in a bluish color. NGC 4676B has a yellowish core and two arcs; arm remnants underneath are bluish as well.

The galaxies were photographed in 2002 by the Hubble Space Telescope.[4] In the background of the Mice Galaxies, there are at least 3300 galaxies, at distances up to 13 billion light-years.

See also

References
  1. "NASA/IPAC Extragalactic Database". Results for NGC 4676A / 4676B. Retrieved 2006-11-21.
  2. Chien, Li-Hsin; Barnes, Joshua E.; Kewley, Lisa J.; Chambers, Kenneth, C. (May 2007). "Multiobject Spectroscopy of Young Star Clusters in NGC 4676". The Astrophysical Journal. 660 (2): L105–L108. arXiv:astro-ph/0703510. Bibcode:2007ApJ...660L.105C. doi:10.1086/518215.CS1 maint: multiple names: authors list (link)
  3. Burbidge, E. M.; Burbidge, G. R. (March 1961). "NGC 4676, a Peculiar System in the Coma Cluster of Galaxies". The Astrophysical Journal. 133: 726. Bibcode:1961ApJ...133..726B. doi:10.1086/147076. ISSN 0004-637X.
  4. "Hubble's New Camera Delivers Breathtaking Views of the Universe". HubbleSite. 2002-04-30. Retrieved 2009-05-07.

Notes
  1. The size of NGC 4676 A is 194,000 ly, while that of NGC 4676 B is 186,000 ly. This would gives 380,000 ly by combining their sizes although the tail is about 2 times larger, giving 760,000 ly.



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