Virgo Cluster

The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc)[2] away in the constellation Virgo. Comprising approximately 1300 (and possibly up to 2000) member galaxies,[3] the cluster forms the heart of the larger Virgo Supercluster, of which the Local Group (containing our Milky Way galaxy) 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 1.2×1015 M☉ out to 8 degrees of the cluster's center or a radius of about 2.2 Mpc.[4]

Virgo Cluster
Virgo Cluster showing the diffuse light between member galaxies. Messier 87 is the largest galaxy (lower left).
Observation data (Epoch J2000)
Constellation(s)Virgo & Coma Berenices
Right ascension 12h 27m[1]
Declination+12° 43′[1]
Brightest memberMessier 49
Number of galaxies~1500[1]
Bautz–Morgan classificationIII[1]
Binding mass1015 M☉

Many of the brighter galaxies in this cluster, including the giant elliptical galaxy Messier 87, were discovered in the late 1770s and early 1780s and subsequently included in Charles Messier's catalogue of non-cometary fuzzy objects. Described by Messier as nebulae without stars, their true nature was not recognized until the 1920s.[upper-alpha 1]

The cluster subtends a maximum arc of approximately 8 degrees centered in the constellation Virgo. Although some of the cluster's most prominent members can be seen with smaller instruments, a 6-inch telescope will reveal about 160 of the cluster's galaxies on a clear night. Its brightest member is the elliptical galaxy Messier 49; however its most famous member is the elliptical galaxy Messier 87, which is located in the center of the cluster.[6]

Characteristics

The cluster is a fairly heterogeneous mixture of spirals and ellipticals.[7] As of 2004, it is believed that the spiral galaxies of the cluster are distributed in an oblong prolate filament, approximately four times as long as it is wide, stretching along the line of sight from the Milky Way.[8] The elliptical galaxies are more centrally concentrated than the spiral galaxies.[9]

The cluster is an aggregate of at least three separate subclumps: Virgo A, centered on M87, a second centered on the galaxy M86, and Virgo B, centered on M49, with some authors including a Virgo C subcluster, centered on the galaxy M60 as well as a LVC (Low Velocity Cloud) subclump, centered on the large spiral galaxy NGC 4216.[10]

Of all of the subclumps, Virgo A, formed by a mixture of elliptical, lenticular, and (usually) gas-poor spiral galaxies,[11] is the dominant one, with a mass of approximately 1014 M☉, which is approximately an order of magnitude larger than the other two subclumps.[12]

Turbulence may prevent galaxy clusters from cooling (Chandra X-ray).

The three subgroups are in the process of merging to form a larger single cluster[12] and are surrounded by other smaller galaxy clouds, mostly composed of spiral galaxies, known as N Cloud, S Cloud, and Virgo E that are in the process of infalling to merge with them,[13] plus other farther isolated galaxies and galaxy groups (like the galaxy cloud Coma I) that are also attracted by the gravity of Virgo to merge with it in the future.[14] This strongly suggests the Virgo cluster is a dynamically young cluster that is still forming.[13]

Other two nearby aggregations known as M Cloud, W Cloud, and W' Cloud[10] seem to be background systems independent of the main cluster.[13]

The large mass of the cluster is indicated by the high peculiar velocities of many of its galaxies, sometimes as high as 1,600 km/s with respect to the cluster's center.

The Virgo cluster lies within the Virgo Supercluster, and its gravitational effect slows down the nearby galaxies. The large mass of the cluster has the effect of slowing down the recession of the Local Group from the cluster by approximately ten percent.

Intracluster medium

As with many other rich galaxy clusters, Virgo's intracluster medium is filled with a hot, rarefied plasma at temperatures of 30 million kelvins that emits X-Rays.[15] Within the intracluster medium (ICM) are found a large number of intergalactic stars[16][17] (up to 10% of the stars in the cluster),[18] including some planetary nebulae.[19] It is theorized that these were expelled from their home galaxies by interactions with other galaxies.[18] The ICM also contains some globular clusters,[20][21][22] possibly stripped off dwarf galaxies,[22] and even at least one star formation region.[23]

Galaxies
Map of the Virgo Supercluster centered on the Local Group (image diameter 200 Mly ≈ 60 Mpc). The Virgo Cluster is visible in the center right of the image, at about 50 Mly from the Local Group.
Photograph of the Virgo Cluster with labelled galaxies

Below is given a table of bright or notable objects in the Virgo Cluster and the subunit of the cluster in which they are located. Note that in some cases a galaxy may be considered in a different subunit by other researchers (sources:[10][13][24][25])

Column 1: The name of the galaxy.
Column 2: The right ascension for epoch 2000.
Column 3: The declination for epoch 2000.
Column 4: The blue apparent magnitude of the galaxy.
Column 5: The galaxy type: E=Elliptical, S0=Lenticular, Sa,Sb,Sc,Sd=Spiral, SBa,SBb,SBc,SBd=Barred spiral, Sm,SBm,Irr=Irregular.
Column 6: The angular diameter of the galaxy (arcminutes).
Column 7: The diameter of the galaxy (thousands of light years).
Column 8: The recessional velocity (km/s) of the galaxy relative to the cosmic microwave background.
Column 9: Subcluster where the galaxy is located.
Cluster members
Designation Coordinates (Epoch 2000) Apparent
magnitude
(blue)		 Type Angular size Diameter
(kly)		 RV
(km/s)		 Subcluster
RA Dec
Messier 9812 13.814 5410.9SBb9.8′150184Virgo A or N Cloud
NGC 421612 15.913 0910.9SBb7.9′120459Virgo A, N Cloud, or LVC.
Messier 9912 18.814 2510.4Sc5.4′802735Virgo A or N Cloud
NGC 426212 19.514 5312.4S01.9′301683Virgo A
NGC 438812 25.512 3911.8SAb6.2′852845Virgo A
Messier 6112 21.904 2810.2SBbc6.2′1001911S Cloud
Messier 10012 22.915 4910.1SBbc7.6′1151899Virgo A
Messier 8412 25.112 5310.1E16.0′901239Virgo A
Markarian's Chain
Messier 8512 25.418 1110.0S07.1′1051056Virgo A
Messier 8612 26.212 579.9E310.2′15537Virgo A or own subgroup.
Markarian's Chain
NGC 443512 27.713 0511.7S03.0′451111Virgo A
NGC 443812 27.813 0111.0Sa8.7′130404Virgo A
NGC 445012 28.517 0510.9Sab5.1′802273Virgo A
Messier 4912 29.808 009.3E29.8′1501204Virgo B
Messier 8712 30.812 239.6E0–19.8′1501204Virgo A
Messier 8812 32.014 2510.3Sb6.8′1002599Virgo A
NGC 452612 32.007 4210.6S07.1′105931Virgo B
NGC 452712 34.102 3912.4Sb4.6′691730S Cloud
NGC 453612 34.402 1111.1SBbc7.2′1152140S Cloud
Messier 9112 35.414 3011.0SBb5.2′80803Virgo A
NGC 454612 35.5-03 4811.3S02.3'301054S Cloud
NGC 455012 35.512 1312.5S03.2′50704Virgo A
Messier 8912 35.712 3310.7E05.0′75628Virgo A
NGC 456712 36.511 1512.1Sbc2.8′402588Virgo A
NGC 456812 36.611 1411.7Sbc4.4′652578Virgo A
Messier 9012 36.813 1010.2SBab10.5′16087Virgo A
NGC 457112 36.914 1311.9Sc3.7′55659Virgo A
Messier 5812 37.711 4910.6SBb5.6′851839Virgo A
Messier 5912 42.911 3910.8E55.0′75751Virgo A or Virgo E
Messier 6012 43.711 339.8E27.2′1101452Virgo A, Virgo E, or Virgo C
NGC 465112 43.716 2411.4Sc4.0′601113
NGC 465412 43.913 0811.1SBc5.0′751349Virgo A

Fainter galaxies within the cluster are usually known by their numbers in the Virgo Cluster Catalog, particularly members of the numerous dwarf galaxy population.[26]

See also

Notes
  1. Following the entry for M91 in the Connoissance des Temps for 1784, Messier added the following note:
    The constellation of Virgo, & especially the northern Wing is one of the constellations which encloses the most Nebulae: this Catalog contains thirteen which have been determined: viz. Nos. 49, 58, 59, 60, 61, 84, 85, 86, 87, 88, 89, 90, & 91. All these nebulae appear to be without stars: one can see them only in a very good sky, & near their meridian passage. Most of these nebulae have been pointed to me by Mr. Méchain.[5]

References
  1. "NASA/IPAC Extragalactic Database". Results for Virgo Cluster. Retrieved 2006-10-19.
  2. Mei, Simona; Blakeslee, John P.; Côté, Patrick; Tonry, John L.; West, Michael J.; Ferrarese, Laura; Jordán, Andrés; Peng, Eric W.; Anthony, André; Merritt, Davi (2007). "The ACS Virgo Cluster Survey. XIII. SBF Distance Catalog and the Three-dimensional Structure of the Virgo Cluster". The Astrophysical Journal. 655 (1): 144–162. arXiv:astro-ph/0702510. Bibcode:2007ApJ...655..144M. doi:10.1086/509598.
  3. "Virgo Cluster". Cosmos. Swinburne University of Technology.
  4. Fouqué, P.; Solanes, J. M.; Sanchis, T.; Balkowski, C. (2001). "Structure, mass and distance of the Virgo cluster from a Tolman-Bondi model". Astronomy and Astrophysics. 375 (3): 770–780. arXiv:astro-ph/0106261. Bibcode:2001A&A...375..770F. doi:10.1051/0004-6361:20010833.
  5. "Messier 91 — Observations and Descriptions". SEDS.
  6. "Virgo Cluster | Messier Objects". www.messier-objects.com. Retrieved 2018-06-24.
  7. Côté, Patrick; Blakeslee, John P.; Ferrarese, Laura; Jordán, Andrés; Mei, Simona; Merritt, David; Milosavljević, Miloš; Peng, Eric W.; Tonry, John L.; et al. (July 2004). "The ACS Virgo Cluster Survey". The Astrophysical Journal. 153 (1): 223–242. arXiv:astro-ph/0404138. Bibcode:2004ApJS..153..223C. doi:10.1086/421490.
  8. M. Fukugita; S. Okamura; N. Yasuda (1993). "Spatial distribution of spiral galaxies in the Virgo Cluster from the Tully-Fisher relation". Astrophysical Journal. 412: L13–L16. Bibcode:1993ApJ...412L..13F. doi:10.1086/186928.
  9. "Virgo Cluster". ned.ipac.caltech.edu. Retrieved 2018-06-24.
  10. Boselli, A.; Voyer, E.; Boissier, S.; Cucciati, O.; Consolandi, G.; Cortese, L.; Fumagalli, M.; Gavazzi, G.; Heinis, S.; Roehlly, Y.; Toloba, E. (2014). "The GALEX Ultraviolet Virgo Cluster Survey (GUViCS). IV. The role of the cluster environment on galaxy evolution". Astronomy & Astrophysics. 570: A69. arXiv:1407.4986. Bibcode:2014A&A...570A..69B. doi:10.1051/0004-6361/201424419. A69.
  11. Chamaraux, P.; Balkowski, C.; Gerard, E. (1980). "The H I deficiency of the Virgo cluster spirals". Astronomy & Astrophysics. 83 (1–2): 38–51. Bibcode:1980A&A....83...38C.
  12. The Virgo Super Cluster: home of M87 (with frames)
  13. Gavazzi, G.; Boselli, A.; Scodeggio, M.; Pierini, D.; Belsole, E. (1999). "The 3D structure of the Virgo cluster from H-band Fundamental Plane and Tully-Fisher distance determinations". Monthly Notices of the Royal Astronomical Society. 304 (3): 595–610. arXiv:astro-ph/9812275. Bibcode:1999MNRAS.304..595G. doi:10.1046/j.1365-8711.1999.02350.x.
  14. Tully, R. B.; Shaya, E. J. (1984). "Infall of galaxies into the Virgo cluster and some cosmological constraints". Astrophysical Journal. 281: 31–55. Bibcode:1984ApJ...281...31T. doi:10.1086/162073.
  15. Lea, S. M.; Mushotzky, R.; Holt, S. S. (1982). "Einstein Observatory solid state spectrometer observations of M87 and the Virgo cluster". Astrophysical Journal. 262 (1): 24–32. Bibcode:1982ApJ...262...24L. doi:10.1086/160392. hdl:2060/19820026438.
  16. Ferguson, H. (1997). "Intergalactic Stars in the Virgo Cluster". HST Proposal: 7411. Bibcode:1997hst..prop.7411F.
  17. Ferguson, Henry C.; Tanvir, Nial R.; von Hippel, Ted (January 1998). "Detection of intergalactic red-giant-branch stars in the Virgo cluster". Nature. 391 (6666): 461–463. arXiv:astro-ph/9801228. Bibcode:1998Natur.391..461F. doi:10.1038/35087. ISSN 0028-0836.
  18. Ferguson, Henry C.; Tanvir, Nial R.; von Hippel, Ted (1998). "Detection of intergalactic red-giant-branch stars in the Virgo cluster". Nature. 391 (6666): 461–463. arXiv:astro-ph/9801228. Bibcode:1998Natur.391..461F. doi:10.1038/35087.
  19. Feldmeier, J.; Ciardullo, R.; Jacoby, G. (1998). "Intracluster Planetary Nebulae in the Virgo Cluster. I. Initial Results". Astrophysical Journal. 503 (1): 109–117. arXiv:astro-ph/9803062. Bibcode:1998ApJ...503..109F. doi:10.1086/305981.
  20. Takamiya, Marianne; West, Michael; Côté, Patrick; Jordán, Andrés; Peng, Eric; Ferrarese, Laura (2009). IGCs in the Virgo Cluster. Globular Clusters – Guides to Galaxies, Eso Astrophysics Symposia, Volume. Eso Astrophysics Symposia. pp. 361–365. Bibcode:2009gcgg.book..361T. doi:10.1007/978-3-540-76961-3_83. ISBN 978-3-540-76960-6.
  21. Durrell, Patrick R.; Accetta, K.; Feldmeier, J. J.; Mihos, J. C.; Ciardullo, R.; Peng, E. W.; Members of the NGVS team (2010). "Searching for Intracluster Globular Clusters in the Virgo Cluster". Bulletin of the American Astronomical Society. 42: 567. Bibcode:2010AAS...21547814D.
  22. Lee, Myung Gyoon; Park, Hong Soo; Hwang, Ho Seong (2010). "Detection of a Large-Scale Structure of Intracluster Globular Clusters in the Virgo Cluster". Science. 328 (5976): 334–. arXiv:1003.2499. Bibcode:2010Sci...328..334L. doi:10.1126/science.1186496. PMID 20223950.
  23. Gerhard, Ortwin; Arnaboldi, Magda; Freeman, Kenneth C.; Okamura, Sadanori (2002). "Isolated Star Formation: A Compact H II Region in the Virgo Cluster". The Astrophysical Journal. 580 (2): L121–L124. arXiv:astro-ph/0211341. Bibcode:2002ApJ...580L.121G. doi:10.1086/345657.
  24. "Galaxy On Line Database Milano Network". GOLDMine. Retrieved 2012-08-06.
  25. "The Virgo Cluster". Retrieved 2013-04-06.
  26. Binggeli, Bruno; Sandage, Allan; Tammann, Gustav (1985). "Studies of the Virgo Cluster. II – A Catalog of 2096 Galaxies in the Virgo Cluster Area". Astronomical Journal. American Astronomical Society. 90: 1681–1759. Bibcode:1985AJ.....90.1681B. doi:10.1086/113874.

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