Mice Galaxies

{{Short description|Two spiral galaxies in the constellation Coma Berenices}}{{More citations needed|date=June 2024}}{{Infobox galaxy

| name = NGC 4676A / 4676B

| image = Merging galaxies NGC 4676 (captured by the Hubble Space Telescope).jpg

| image_size = 300px

| caption = The Mice Galaxies, NGC 4676A (right) / NGC 4676B (left)

| epoch = J2000

| type = Irr / SB(s)0/a pec{{cite web

| title=NASA/IPAC Extragalactic Database

| work=Results for NGC 4676A / 4676B

| url=http://nedwww.ipac.caltech.edu/

| access-date=2006-11-21 }}

| ra = {{RA|12|46|10.1}} / {{RA|12|46|11.2}}

| dec = {{DEC|+30|43|55}} / {{DEC|+30|43|22}}

| dist_ly = {{cvt|290|Mly|Mpc|lk=on}}

| z = 6613 ± 8 / 6607 ± 7 km/s

| appmag_v = 14.7 / 14.4

| size_v = 2′.3 × 0′.7 / 2′.2 × 0′.8

| size = {{cvt|233|kpc|ly|lk=on|order=flip}} (estimated){{efn|name=size|The size of NGC 4676 A is 194,000 ly, while that of NGC 4676 B is 186,000 ly. This would give 380,000 ly by combining their sizes although the tail is about two times larger, giving 760,000 ly.}}

| constellation name = Coma Berenices

| notes = Interacting galaxies

| names = Mice Galaxies, IC 819 / 820, UGC 7938 / 7939,

PGC 43062 / 43065, Arp 242

}}

NGC 4676, or the Mice Galaxies, are two spiral galaxies in the constellation Coma Berenices. About 290 million light-years distant,{{cite journal

| first = Li-Hsin | last = Chien

| last2 = Barnes | first2 = Joshua E.

| last3 = Kewley | first3 = Lisa J.

| last4 = Chambers | first4 = Kenneth, C.

| title = Multiobject Spectroscopy of Young Star Clusters in NGC 4676

| date = May 2007

| journal = The Astrophysical Journal

| volume = 660

| issue = 2

| pages = L105–L108

| bibcode = 2007ApJ...660L.105C

| doi = 10.1086/518215|arxiv = astro-ph/0703510 | s2cid = 119417388

}} they have begun the process of colliding and merging. Their "mice" 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,{{Cite journal|last1=Burbidge|first1=E. M.|last2=Burbidge|first2=G. R.|date=March 1961|title=NGC 4676, a Peculiar System in the Coma Cluster of Galaxies.|bibcode=1961ApJ...133..726B|journal=The Astrophysical Journal|language=en|volume=133|pages=726|doi=10.1086/147076|issn=0004-637X}} have experienced collision, and will continue colliding until they coalesce.

The colors of the galaxies 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.{{citation-needed|date=October 2023}}{{clarify|date=May 2018|reason=Which side is the "beginning" and which side is the "end"?}} 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.{{cite news|title=Hubble's New Camera Delivers Breathtaking Views of the Universe|work=HubbleSite|date=2002-04-30|url=https://hubblesite.org/contents/news-releases/2002/news-2002-11|access-date=2009-05-07}} In the background of the Mice Galaxies, there are over 3000 galaxies, at distances up to 13 billion light-years.