Coma Cluster

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Coma Cluster
Coma cluster leo.jpg
Coma cluster of galaxies photographed by an amateur
Observation data (Epoch J2000)
Constellation(s) Coma Berenices
Right ascension 12h 59m 48.7s [1]
Declination +27° 58′ 50″ [1]
Brightest member NGC 4874 and NGC 4889
Number of galaxies> 1000 [2] [3]
Richness class 2 [4]
Bautz–Morgan classification II [4]
Velocity dispersion 1,000 km/s [5]
Redshift 0.0231 (6 925 km/s) [1]
Distance 102.975  Mpc (336  Mly) for h−1
0.705 [1]
ICM temperature 8-9 keV [6]
Binding mass ~7×1014 [7]   M☉
X-ray flux (319.20 ± 2.6%)×10−12 erg s−1 cm−2 [1] (0.1-2.4 keV) [1]
Other designations
Abell 1656 [1]
See also: Galaxy group, Galaxy cluster, List of galaxy groups and clusters

The Coma Cluster (Abell 1656) is a large cluster of galaxies that contains over 1,000 identified galaxies. [2] [3] Along with the Leo Cluster (Abell 1367), it is one of the two major clusters comprising the Coma Supercluster. [8] It is located in and takes its name from the constellation Coma Berenices.

Contents

The cluster's mean distance from Earth is 99 Mpc (321 million light years). [3] [9] [10] Its ten brightest spiral galaxies have apparent magnitudes of 12–14 that are observable with amateur telescopes larger than 20 cm. [11] The central region is dominated by two supergiant elliptical galaxies: NGC 4874 and NGC 4889. [12] 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. [13]

Cluster members

Tails in spiral galaxy D100, found in the Coma Cluster, are created by ram-pressure stripping. Wading through water.jpg
Tails in spiral galaxy D100, found in the Coma Cluster, are created by ram-pressure stripping.

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. [16] [17] [18]

Dark matter

The Coma Cluster is one of the first places where observed gravitational anomalies were considered to be indicative of unobserved mass. In 1933 Fritz Zwicky showed that the galaxies of the Coma Cluster were moving too fast for the cluster to be bound together by the visible matter of its galaxies. Though the idea of dark matter would not be accepted for another fifty years, Zwicky wrote that the galaxies must be held together by "dunkle Materie" (dark matter). [19] [20]

About 90% of the mass of the Coma cluster is believed to be in the form of dark matter. The distribution of dark matter throughout the cluster, however, is poorly constrained[ clarification needed ]. [21]

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. [22] 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. [23] 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 to be designated Coma X-1. [24]

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. [24] 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. [24] The Uhuru observations indicated a source strength of no greater than ~10−3 photons cm−2s−1keV−1 at 25 keV, [24] which disagrees with the earlier observations [22] claiming a source strength of ~10−2 photons cm−2s−1keV−1 at 25 keV, and a size of 5°.

See also

Related Research Articles

In astronomy, dark matter is a hypothetical form of matter that appears not to interact with light or the electromagnetic field. Dark matter is implied by gravitational effects which cannot be explained by general relativity unless more matter is present than can be seen. Such effects occur in the context of formation and evolution of galaxies, gravitational lensing, the observable universe's current structure, mass position in galactic collisions, the motion of galaxies within galaxy clusters, and cosmic microwave background anisotropies.

<span class="mw-page-title-main">Galaxy</span> Large gravitationally bound system of stars and interstellar matter

A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek galaxias (γαλαξίας), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a thousand stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies.

<span class="mw-page-title-main">Virgo Cluster</span> Galaxy cluster in the constellation Virgo

The Virgo Cluster is a large cluster of galaxies whose center is 53.8 ± 0.3 Mly away in the constellation Virgo. Comprising approximately 1,300 member galaxies, the cluster forms the heart of the larger Virgo Supercluster, of which the Local Group is a member. The Local Group actually experiences the mass of the Virgo Supercluster as the Virgocentric flow. It is estimated that the Virgo Cluster's mass is 1.2×1015M☉ out to 8 degrees of the cluster's center or a radius of about 2.2 Mpc.

<span class="mw-page-title-main">Messier 87</span> Elliptical galaxy in the Virgo Galaxy Cluster

Messier 87 is a supergiant elliptical galaxy in the constellation Virgo that contains several trillion stars. One of the largest and most massive galaxies in the local universe, it has a large population of globular clusters—about 15,000 compared with the 150–200 orbiting the Milky Way—and a jet of energetic plasma that originates at the core and extends at least 1,500 parsecs, traveling at a relativistic speed. It is one of the brightest radio sources in the sky and a popular target for both amateur and professional astronomers.

<span class="mw-page-title-main">Astronomical spectroscopy</span> Study of astronomy using spectroscopy to measure the spectrum of electromagnetic radiation

Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, ultraviolet, X-ray, infrared and radio waves that radiate from stars and other celestial objects. A stellar spectrum can reveal many properties of stars, such as their chemical composition, temperature, density, mass, distance and luminosity. Spectroscopy can show the velocity of motion towards or away from the observer by measuring the Doppler shift. Spectroscopy is also used to study the physical properties of many other types of celestial objects such as planets, nebulae, galaxies, and active galactic nuclei.

<span class="mw-page-title-main">Pinwheel Galaxy</span> Galaxy in the constellation Ursa Major

The Pinwheel Galaxy is a face-on spiral galaxy located 21 million light-years from Earth in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 and was communicated that year to Charles Messier, who verified its position for inclusion in the Messier Catalogue as one of its final entries.

<span class="mw-page-title-main">Abell 2218</span> Galaxy cluster in the constellation Draco

Abell 2218 is a large cluster of galaxies over 2 billion light-years away in the constellation Draco.

<span class="mw-page-title-main">Centaurus A</span> Radio galaxy in the constellation Centaurus

Centaurus A is a galaxy in the constellation of Centaurus. It was discovered in 1826 by Scottish astronomer James Dunlop from his home in Parramatta, in New South Wales, Australia. There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type and distance. NGC 5128 is one of the closest radio galaxies to Earth, so its active galactic nucleus has been extensively studied by professional astronomers. The galaxy is also the fifth-brightest in the sky, making it an ideal amateur astronomy target. It is only visible from the southern hemisphere and low northern latitudes.

<span class="mw-page-title-main">Fritz Zwicky</span> Swiss astronomer (1898–1974)

Fritz Zwicky was a Swiss astronomer. He worked most of his life at the California Institute of Technology in the United States of America, where he made many important contributions in theoretical and observational astronomy. In 1933, Zwicky was the first to use the virial theorem to postulate the existence of unseen dark matter, describing it as "dunkle Materie".

<span class="mw-page-title-main">Sombrero Galaxy</span> Galaxy in the constellation Virgo

The Sombrero Galaxy is a peculiar galaxy of unclear classification in the constellation borders of Virgo and Corvus, being about 9.55 megaparsecs from the Milky Way galaxy. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It has an isophotal diameter of approximately 29.09 to 32.32 kiloparsecs, making it slightly bigger in size than the Milky Way.

<span class="mw-page-title-main">Messier 84</span> Galaxy in the constellation Virgo

Messier 84 or M84, also known as NGC 4374, is a giant elliptical or lenticular galaxy in the constellation Virgo. Charles Messier discovered the object in 1781 in a systematic search for "nebulous objects" in the night sky. It is the 84th object in the Messier Catalogue and in the heavily populated core of the Virgo Cluster of galaxies, part of the local supercluster.

<span class="mw-page-title-main">I Zwicky 18</span> Dwarf irregular galaxy in the constellation Ursa Major

I Zwicky 18 is a blue compact dwarf galaxy located about 59 million light years away in the constellation Ursa Major. The galaxy was first identified by Swiss astronomer Fritz Zwicky in a 1930s photographic survey of galaxies.

<span class="mw-page-title-main">Perseus Cluster</span> Galaxy cluster in the constellation Perseus

The Perseus cluster is a cluster of galaxies in the constellation Perseus. It has a recession speed of 5,366 km/s and a diameter of 863′. It is one of the most massive objects in the known universe, containing thousands of galaxies immersed in a vast cloud of multimillion-degree gas.

<span class="mw-page-title-main">IC 1101</span> Galaxy in the constellation Virgo

IC 1101 is a class S0 supergiant (cD) lenticular galaxy at the center of the Abell 2029 galaxy cluster. It has an isophotal diameter at about 123.65 to 169.61 kiloparsecs. It possesses a diffuse core which is the largest known core of any galaxy to date, and contains a supermassive black hole, one of the largest discovered. The galaxy is located at 354.0 megaparsecs from Earth. The galaxy was discovered on 19 June 1790, by the British astronomer William Herschel.

<span class="mw-page-title-main">Abell 1413</span> Galaxy cluster in constellation Coma Berenices

Abell 1413 is a massive and rich type I galaxy cluster straddling the border between the constellations Leo and Coma Berenices, with the projected comoving distance of approximately 640 Mpc (2.1 billion ly). The cluster is especially notable due to the presence of its very large brightest cluster galaxy (BCG), one of the most extreme examples of its type, as well as one of the largest galaxies known. The cluster was first noted by George O. Abell in 1958.

<span class="mw-page-title-main">NGC 4494</span> Galaxy in the constellation Coma Berenices

NGC 4494 is an elliptical galaxy located in the constellation Coma Berenices. It is located at a distance of circa 45 million light years from Earth, which, given its apparent dimensions, means that NGC 4494 is about 60,000 light years across. It was discovered by William Herschel in 1785.

<span class="mw-page-title-main">NGC 3311</span> Galaxy in the constellation Hydra

NGC 3311 is a super-giant elliptical galaxy located about 190 million light-years away in the constellation Hydra. The galaxy was discovered by astronomer John Herschel on March 30, 1835. NGC 3311 is the brightest member of the Hydra Cluster and forms a pair with NGC 3309 which along with NGC 3311, dominate the central region of the Hydra Cluster.

<span class="mw-page-title-main">NGC 547</span> Galaxy in the constellation Cetus

NGC 547 is an elliptical galaxy and radio galaxy located in the constellation Cetus. It is located at a distance of about 220 million light years from Earth, which, given its apparent dimensions, means that NGC 547 is about 120,000 light years across. It was discovered by William Herschel on October 1, 1785. It is a member of the Abell 194 galaxy cluster and is included along with NGC 547 in the Atlas of Peculiar Galaxies.

References

  1. 1 2 3 4 5 6 7 "NASA/IPAC Extragalactic Database". Results for Abell 1656. Retrieved 2006-09-19.
  2. 1 2 "Chandra/Field Guide to X-ray Sources". Coma Cluster. Archived from the original on April 21, 2008. Retrieved 2008-06-16.
  3. 1 2 3 "NASA / Focus on the Coma Cluster". Archived from the original on 2008-05-30. Retrieved 2008-06-16.
  4. 1 2 Abell, George O.; Corwin, Harold G. Jr.; Olowin, Ronald P. (May 1989). "A catalog of rich clusters of galaxies". Astrophysical Journal Supplement Series. 70 (May 1989): 1–138. Bibcode:1989ApJS...70....1A. doi: 10.1086/191333 . ISSN   0067-0049.
  5. ↑ Struble, Mitchell F.; Rood, Herbert J. (November 1999). "A Compilation of Redshifts and Velocity Dispersions for ACO Clusters". The Astrophysical Journal Supplement Series. 125 (1). Chicago, Illinois, USA: The University of Chicago Press: 35–71. Bibcode:1999ApJS..125...35S. doi: 10.1086/313274 .
  6. ↑ 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. doi:10.1093/pasj/63.sp3.s991 . Retrieved March 12, 2012.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ↑ Gavazzi, R.; Adami, C.; Durret, F.; Cuillandre, J.-C.; Ilbert, O.; Mazure, A.; Pelló, R.; Ulmer, M.P. (May 2009). "A weak lensing study of the Coma cluster". Astronomy and Astrophysics . 498 (2): L33–L36. arXiv: 0904.0220 . Bibcode:2009A&A...498L..33G. doi:10.1051/0004-6361/200911841. S2CID   15418452.
  8. ↑ "The Coma Supercluster".
  9. ↑ "2MASS Atlas Image Gallery: Galaxy Groups and Clusters". Infrared Processing and Analysis Center. Retrieved 2010-05-02.
  10. ↑ Colless, M (2001). "Coma Cluster". In P Murdin (ed.). Encyclopedia of Astronomy and Astrophysics. Bristol Institute of Physics publishing. Retrieved 2006-10-08.[ permanent dead link ]
  11. ↑ Singapore Science Centre. "ScienceNet - Astronomy & Space Science - Observatories/ Telescopes - Question No. 13490". Archived from the original on 2005-11-11. Retrieved 2012-02-25.
  12. ↑ Conselice, Christopher J., Gallagher, John S., III (1998). "Galaxy aggregates in the Coma cluster". 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. S2CID   14908115.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ↑ Newswise: Hubble's Sweeping View of the Coma Cluster of Galaxies Retrieved on June 11, 2008.
  14. ↑ "Wading through water". www.spacetelescope.org. Retrieved 28 January 2019.
  15. ↑ Cramer, William J.; et al. (Jan 2019). "Spectacular Hubble Space Telescope Observations of the Coma Galaxy D100 and Star Formation in Its Ram Pressure–stripped Tail". The Astrophysical Journal. 870 (2): 2. arXiv: 1811.04916 . Bibcode:2019ApJ...870...63C. doi: 10.3847/1538-4357/aaefff . S2CID   119218554.
  16. ↑ Zwicky, Fritz (October 1937). "On the Masses of Nebulae and of Clusters of Nebulae". Astrophysical Journal . 86 (3): 217–246. Bibcode:1937ApJ....86..217Z. doi: 10.1086/143864 .
  17. ↑ Shapley, Harlow (July 1934). "A Photometric Investigation of Wolf's Cluster of Nebulae in Coma". Harvard College Observatory Bulletin. 896. Cambridge, MA, USA: 3–12. Bibcode:1934BHarO.896....3S.
  18. ↑ Wallenquist, Å. (1933). "On the space distribution of the nebulae in the Coma Cluster". Annalen V.d. Bosscha-Sterrenwacht (Miscellaneous Papers (Observatorium Bosscha)). 4 (6). France: Bandoeng : Gebrs. Kleijne: 73–77. Bibcode:1933AnBos...4...73W.
  19. ↑ Zwicky, F. (1933). "Die Rotverschiebung von extragalaktischen Nebeln" [The red shift of extragalactic neubulae]. Helvetica Physica Acta (in German). 6: 110–127. Bibcode:1933AcHPh...6..110Z. From p 125: "Um, wie beobachtet, einen mittleren Dopplereffekt von 1000 km/sek oder mehr zu erhalten, müsste also die mittlere Dichte im Comasystem mindestens 400 mal grösser sein als die auf Grund von Beobachtungen an leuchtender Materie abgeleitete. Falls sich dies bewahrheiten sollte, würde sich also das überraschende Resultat ergeben, dass dunkle Materie in sehr viel grösserer Dichte vorhanden ist als leuchtende Materie." (In order to obtain an average Doppler effect of 1000 km/s or more, as observed, the average density in the Coma system would thus have to be at least 400 times greater than that derived on the basis of observations of luminous matter. If this were to be verified, the surprising result would then follow that dark matter is present in very much greater density than luminous matter.)
  20. ↑ de Swart, J. G.; Bertone, G.; van Dongen, J. (2017). "How dark matter came to matter". Nature Astronomy. 1 (59): 0059. arXiv: 1703.00013 . Bibcode:2017NatAs...1E..59D. doi:10.1038/s41550-017-0059. S2CID   119092226.
  21. ↑ Merritt, D. (February 1987). "The Distribution of Dark Matter in the Coma Cluster". The Astrophysical Journal. 313: 121–135. Bibcode:1987ApJ...313..121M. doi: 10.1086/164953 .
  22. 1 2 Boldt E, McDonald FB, Riegler G, Serlemitsos P (1966). "Extended source of energetic cosmic X rays". Phys. Rev. Lett. 17 (8): 447–50. Bibcode:1966PhRvL..17..447B. doi:10.1103/PhysRevLett.17.447.
  23. ↑ Friedman H, Byram ET (January 1967). "X-rays from the Coma cluster of galaxies". Astrophysical Journal. 147 (1): 399–401. Bibcode:1967ApJ...147..368.. doi:10.1086/149022. S2CID   4286878.
  24. 1 2 3 4 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". Astrophysical Journal. 167 (8): L81–4. Bibcode:1971ApJ...167L..81G. doi: 10.1086/180765 .
  25. ↑ "Clusters within clusters". www.spacetelescope.org. Retrieved 3 December 2018.
  26. ↑ "Hubble close-up on the Coma Cluster". ESA/Hubble Picture of the Week. Retrieved 18 January 2014.
  27. ↑ "Coma Cluster".
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