Coma Cluster

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This article is about the cluster of galaxies named the Coma Cluster. For the star cluster, see Coma star cluster.

**Coma Cluster**
Observation data (Epoch J2000)
Galaxy groups and clusters	List of galaxy groups and clusters
Map of the central part of the Coma Cluster
Constellation(s):	Coma Berenices
Right ascension	12^h 59^m 49^s^[1]
Declination	+27° 58′ 50″^[1]
Number of galaxies:	484^[1]
Brightest member:
Other designations
Abell 1656^[1]

The Coma Cluster (Abell 1656) is a large cluster that contains over 1000 identified galaxies^{[citation needed]}.

The cluster's mean distance from Earth is 99 Mpc (321 million light years)^[2] . Its 10 brightest spiral galaxies have apparent magnitudes of 12-14 that are observable with amateur telescopes larger than 20 cm^{[citation needed]}. The central region is dominated by two giant elliptical galaxies: NGC 4874 and NGC 4889^[3].

1 Intracluster gas
2 Cluster members
3 See also
4 External links
5 References

[edit] Intracluster gas

The galaxies in this cluster are surrounded by very hot intracluster gas that produces significant X-ray emission^{[citation needed]}. This ionized gas also shifts the microwave spectrum of the cosmic microwave background radiation, an effect called Sunyaev-Zel'dovich effect^[4]. The mass of the intracluster gas is much higher than the mass of all the galaxies in the cluster^{[citation needed]}.

[edit] 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^{[citation needed]}, although many of the individual galaxies in the cluster had been identified previously^{[citation needed]}.

[edit] See also

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

[edit] External links

NASA: The Coma Cluster of Galaxies

[edit] References

^ ^a ^b ^c ^d NASA/IPAC Extragalactic Database. Results for Abell 1656. Retrieved on 2006-09-19.
^ Colless, M. (2001). "Coma Cluster". Encyclopedia of Astronomy and Astrophysics. Ed. P Murdin. Bristol Institute of Physics publishing. Retrieved on 2006-10-08.
^ Conselice, Christopher J., Gallagher, John S., III (1998). "Galaxy aggregates in the Coma cluster". Monthly Notices of the Royal Astronomical Society 297: L34-L38.
^ M. De Petris, L. D'Alba, L. Lamagna, F. Melchiorri, A. Orlando, E. Palladino, Y. Rephaeli, S. Colafrancesco, E. Kreysa, M. Signore (2002). "MITO Measurements of the Sunyaev-Zeldovich Effect in the Coma Cluster of Galaxies". Astrophysical Journal 574: L119-L122.