This article is about the cluster of galaxies named the Coma Cluster. For the star cluster, see Coma star cluster. Not to be confused with the Coma cluster of galaxies The Coma Star Cluster in Coma Berenices, designated

Coma Cluster
A Sloan Digital Sky Survey/Spitzer Space Telescope image of the Coma Cluster in ultraviolet and visible light Courtesy: NASA/JPL-Caltech/GSFC/SDSS
Observation data (Epoch J2000)
Constellation(s)	Coma Berenices
Right ascension	12h 59m 49s[1]
Declination	+27° 58′ 50″[1]
Number of galaxies	484[1]
Other designations
Abell 1656[1]
See also: Galaxy groups and clusters, List of galaxy clusters
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The Coma Cluster (Abell 1656) is a large cluster of galaxies that contains over 1,000 identified galaxies. The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic Redshift survey using a dedicated 2 The Spitzer Space Telescope (formerly the Space Infrared Telescope Facility, SIRTF) is an Infrared Space observatory. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays For other uses see Visibility. Visible is billed as a not-for-profit free quarterly magazine dedicated to the history of The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program The California Institute of Technology (commonly referred to as Caltech) is a private, Coeducational research university located in Pasadena The Goddard Space Flight Center ( GSFC) is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. In common usage a constellation is a group of celestial bodies that are connected together in some arrangement typically stars to form a visible figure or picture Coma Berenices ( Berenice 's Hair) is a traditional asterism that has since become a Constellation. Right ascension (abbrev RA; symbol α) is the Astronomical term for one of the two Coordinates of a point on the Celestial sphere In Astronomy, declination (abbrev dec or δ) is one of the two coordinates of the Equatorial coordinate system, the other being either Galaxy groups and clusters are the largest Gravitationally bound objects to have arisen thus far in the process of cosmic structure formation This page lists some of the more interesting Galaxy clusters and groups The Abell catalogue is an almost complete catalogue of approximately 4000 Galaxy clusters with at least 30 members to a Redshift of z = 0 Galaxy groups and clusters are the largest Gravitationally bound objects to have arisen thus far in the process of cosmic structure formation Along with the Leo Cluster (Abell 1367), it is one of the two major clusters comprising the Coma Supercluster. The Leo Cluster ( Abell 1367 is a galaxy cluster about 330 million Light-years distant ( z = 0 The Coma Supercluster is a nearby Supercluster of Galaxies comprising the Coma Cluster (Abell 1656 and the Leo Cluster (Abell 1367 [1]

The cluster's mean distance from Earth is 99 Mpc (321 million light years). History The first direct measurements of an object at interstellar distances were undertaken by German Astronomer Friedrich Wilhelm Bessel in 1838 A light-year or light year (symbol ly) is a unit of Length, equal to just under ten trillion Kilometres As defined by ^[2] Its ten brightest spiral galaxies have apparent magnitudes of 12–14 that are observable with amateur telescopes larger than 20 cm. The apparent magnitude ( m) of a celestial body is a measure of its Brightness as seen by an observer on Earth, normalized to the value The central region is dominated by two giant elliptical galaxies: NGC 4874 and NGC 4889. An elliptical galaxy is a Galaxy belonging to one of the three main classes of galaxy originally described by Edwin Hubble (whose name was dedicated NGC 4889, also Caldwell 35, is a supergiant class-4 Elliptical galaxy, the brightest within the Coma cluster and a Caldwell object in the constellation ^[3] 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, as well as giant ellipticals, are found in abundance in the Coma Cluster. ^[4]

Cluster members

An image of the Coma Cluster Credit: NASA/Expedition 6

Map of the central part of the Coma Cluster

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 National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program Crew Kenneth Bowersox (5 Commander - NASA Nikolai Budarin (3 Flight Engineer - RSA Donald A lenticular galaxy is a type of Galaxy which is intermediate between an Elliptical galaxy and a Spiral galaxy in Galaxy morphological classification

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. Year 1950 ( MCML) was a Common year starting on Sunday (link will display the full calendar of the Gregorian calendar. Palomar Observatory is a privately owned Observatory located in San Diego County California, 90 miles (145 Km) Southeast of Mount Wilson

See also

• Fornax Cluster - another nearby cluster of galaxies
• Virgo Cluster - another nearby cluster of galaxies

External links

• NASA APOD: The Coma Cluster of Galaxies
• The dynamical state of the Coma cluster with XMM-Newton
• Very Small Array observations of the Sunyaev-Zel'dovich effect in nearby galaxy clusters
• The Coma Cluster on the WikiSky: DSS2, SDSS, IRAS, Hidrogen α, X-Ray, Astrophoto, Sky Map

References

1. ^ ^{a b c d} NASA/IPAC Extragalactic Database. At a distance of approximately 620 Mly (190 Mpc) the Fornax Cluster is the second richest cluster of galaxies within 100 million light-years although The Virgo Cluster is a cluster of galaxies at a distance of approximately 59 ± 4 Mly (18 Results for Abell 1656. Retrieved on 2006-09-19. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 335 - Dalmatius is raised to the rank of Caesar by his uncle Constantine I.
2. ^ Colless, M (2001). "Coma Cluster". Encyclopedia of Astronomy and Astrophysics. Ed. P Murdin. Bristol Institute of Physics publishing. Retrieved on 2006-10-08. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 314 - Roman Emperor Licinius is defeated by his colleague Constantine I at the Battle of Cibalae, and loses  
3. ^ Conselice, Christopher J. , Gallagher, John S. , III (1998). "Galaxy aggregates in the Coma cluster". Monthly Notices of the Royal Astronomical Society 297: L34–L38. doi:10.1046/j.1365-8711.1998.01717.x. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document.  
4. ^ Newswise: Hubble's Sweeping View of the Coma Cluster of Galaxies Retrieved on June 11, 2008.