A Sloan Digital Sky Survey/Spitzer Space Telescope mosaic of the Coma Cluster in long-wavelength infrared (red), short-wavelength infrared (green), and visible light. The many faint green smudges are dwarf galaxies in the cluster.
|Observation data (Epoch J2000)|
|Right ascension||12h 59m 49s|
|Declination||+27° 58′ 50″|
|Brightest member||NGC 4874 and NGC 4889|
|Number of galaxies||> 1000|
|Bautz-Morgan type||II |
|Velocity dispersion||1,000 km/s|
|Redshift||0.0231 (6 925 km/s)|
|102 Mpc (333 Mly) h−1
|ICM temperature||8-9 keV|
|Binding mass||~7×1014 M☉|
|X-ray flux||(319.20 ± 2.6%)×10−12 erg s-1 cm-2 (0.1-2.4 keV)|
The Coma Cluster (Abell 1656) is a large cluster of galaxies that contains over 1,000 identified galaxies. Along with the Leo Cluster (Abell 1367), it is one of the two major clusters comprising the Coma Supercluster. It is located in and takes its name from the constellation Coma Berenices.
The cluster's mean distance from Earth is 99 Mpc (321 million light years). Its ten brightest spiral galaxies have apparent magnitudes of 12–14 that are observable with amateur telescopes larger than 20 cm. The central region is dominated by two giant elliptical galaxies: NGC 4874 and NGC 4889. The cluster is within a few degrees of the north galactic pole on the sky. Most of the galaxies that inhabit the central portion of the Coma Cluster are ellipticals. Both dwarf and giant ellipticals are found in abundance in the Coma Cluster.
Cluster members 
As is usual for clusters of this richness, the galaxies are overwhelmingly elliptical and S0 galaxies, with only a few spirals of younger age, and many of them probably near the outskirts of the cluster.
The full extent of the cluster was not understood until it was more thoroughly studied in the 1950s by astronomers at Mount Palomar Observatory, although many of the individual galaxies in the cluster had been identified previously.
Dark matter 
X-ray source 
An extended X-ray source centered at 1300+28 in the direction of the Coma cluster of galaxies was reported before August 1966. This X-ray observation was performed by balloon, but the source was not detected in the sounding rocket flight launched by the X-ray astronomy group at the Naval Research Laboratory on November 25, 1964. A strong X-ray source was observed by the X-ray observatory satellite Uhuru close to the center of the Coma cluster and this source was suggested be designated Coma X-1.
The Coma cluster contains about 800 galaxies within a 100 x 100 arc-min area of the celestial sphere. The source near the center at RA (1950) 12h56m ± 2m Dec 28°6' ± 12' has a luminosity Lx = 2.6 x 1044 ergs/s. As the source is extended, with a size of about 45', this argues against the possibility that a single galaxy is responsible for the emission. The Uhuru observations indicated a source strength of no greater than ~10−3 photons cm−2s−1keV−1 at 25 keV, which disagrees with the earlier observations claiming a source strength of ~10−2 photons cm−2s−1keV−1 at 25 keV, and a size of 5°.
See also 
- List of Galaxy Clusters
- Eridanus Cluster
- Fornax Cluster - another nearby cluster of galaxies
- Norma Cluster
- Virgo Cluster - another nearby cluster of galaxies
- X-1 X-ray source
- "NASA/IPAC Extragalactic Database". Results for Abell 1656. Retrieved 2006-09-19.
- "Chandra/Field Guide to X-ray Sources". Coma Cluster. Archived from the original on 2008-04-21. Retrieved 2008-06-16. Chandra/Field Guide to X-ray Sources: Coma Cluster at the Wayback Machine (archived February 21, 2008)
- "NASA / Focus on the Coma Cluster". Retrieved 2008-06-16.
- Abell, George O.; Corwin, Harold G., Jr.; Olowin, Ronald P. (May 1989). "A catalog of rich clusters of galaxies" (PDF). Astrophysical Journal Supplement Series 70 (May 1989): 1–138. Bibcode:1989ApJS...70....1A. doi:10.1086/191333. ISSN 0067-0049. Retrieved March 12, 2012.
- Struble, Mitchell F.; Rood, Herbert J. (November 1999). "A Compilation of Redshifts and Velocity Dispersions for ACO Clusters" (PDF). The Astrophysical Journal Supplement Series (Chicago, Illinois, USA: The University of Chicago Press) 125 (1): 35–71. Bibcode:1999ApJS..125...35S. doi:10.1086/313274. Retrieved March 11, 2012.
- Section 4 of Sato, Takuya; Matsushita, Kyoko; Ota, Naomi; Sato, Kosuke; Nakazawa, Kazuhiro; Sarazin, Craig L. (November 2011). "Suzaku Observations of Iron K-Lines from the Intracluster Medium of the Coma Cluster" (PDF). Publications of the Astronomical Society of Japan 63 (SP3): S991–S1007. arXiv:1109.0154. Bibcode:2011PASJ...63S.991S. Retrieved March 12, 2012.
- Gavazzi, R.; Adami, C.; +6 others (May 2009). "A weak lensing study of the Coma cluster" (PDF). Astronomy and Astrophysics 498 (2): L33–L36. arXiv:0904.0220. Bibcode:2009A&A...498L..33G. doi:10.1051/0004-6361/200911841. Retrieved 2012-02-26.
- "The Coma Supercluster".
- "2MASS Atlas Image Gallery: Galaxy Groups and Clusters". Infrared Processing and Analysis Center. Retrieved 2010-05-02.
- Colless, M (2001). "Coma Cluster". In P Murdin. Encyclopedia of Astronomy and Astrophysics. Bristol Institute of Physics publishing. Retrieved 2006-10-08.
- Singapore Science Centre. "ScienceNet - Astronomy & Space Science - Observatories/ Telescopes - Question No. 13490". Archived from the original
|url=(help) on 2002. Retrieved 2012-02-25.
- Conselice, Christopher J., Gallagher, John S., III (1998). "Galaxy aggregates in the Coma cluster" (PDF). Monthly Notices of the Royal Astronomical Society 297 (2): L34–L38. arXiv:astro-ph/9801160. Bibcode:1998MNRAS.297L..34C. doi:10.1046/j.1365-8711.1998.01717.x. Retrieved March 6, 2012.
- Newswise: Hubble's Sweeping View of the Coma Cluster of Galaxies Retrieved on June 11, 2008.
- Zwicky, Fritz (October 1937). "On the Masses of Nebulae and of Clusters of Nebulae" (PDF). Astrophysical Journal 86 (3): 217–246. Bibcode:1937ApJ....86..217Z. doi:10.1086/143864. Retrieved 2012-02-25.
- Shapley, Harlow (July 1934). "A Photometric Investigation of Wolf's Cluster of Nebulae in Coma" (PDF). Harvard College Observatory Bulletin No. 896 (Cambridge, MA, USA): 3–12. Bibcode:1934BHarO.896....3S. Retrieved 2012-02-25.
- Wallenquist, Å. (1933). "On the space distribution of the nebulae in the Coma Cluster" (PDF). Annalen v.d. Bosscha-Sterrenwacht (Miscellaneous papers (Observatorium Bosscha)) (France: Bandoeng : Gebrs. Kleijne) 4 (6): 73–77. Bibcode:1933AnBos...4...73W. Retrieved 2012-02-25.
- Merritt, D. (February 1987). "The Distribution of Dark Matter in the Coma Cluster" (PDF). The Astrophysical Journal 313: 121–135. Bibcode:1987ApJ...313..121M. doi:10.1086/164953. Retrieved March 6, 2012.
- Boldt E, McDonald FB, Riegler G, Serlemitsos P (1966). "Extended source of energetic cosmic X rays" (GIF). Phys Rev Lett. 17 (8): 447–50. Bibcode:1966PhRvL..17..447B. doi:10.1103/PhysRevLett.17.447. Retrieved March 6, 2012.
- Friedman H, Byram ET (January 1967). "X-rays from the Coma cluster of galaxies" (PDF). Astrophysical Journal 147 (1): 399–401. Bibcode:1967ApJ...147..368.. doi:10.1086/149022. Retrieved March 6, 2012.
- Gursky H, Kellogg E, Murray S, Leong C, Tananbaum H, Giacconi R (Aug 1971). "A strong X-ray source in the Coma cluster observed by Uhuru" (PDF). Astrophysical Journal 167 (8): L81–4. Bibcode:1971ApJ...167L..81G. doi:10.1086/180765. Retrieved March 6, 2012.
- The Coma Cluster of Galaxies - Astronomy Picture of the Day, NASA, 2000 August 6
- The dynamical state of the Coma cluster with XMM-Newton
- Very Small Array observations of the Sunyaev-Zel'dovich effect in nearby galaxy clusters
- Hubble Space Telescope Treasury Survey of the Coma Cluster
- The Coma Cluster on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images