The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the constellation Virgo. Comprising approximately 1300 (and possibly up to 2000) member galaxies, 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.
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.[A]
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.
|Observation data (Epoch J2000)|
|Constellation(s)||Virgo & Coma Berenices|
|Right ascension||12h 27m|
|Brightest member||Messier 49|
|Number of galaxies||~1500|
The cluster is a fairly heterogeneous mixture of spirals and ellipticals. 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. The elliptical galaxies are more centrally concentrated than the spiral galaxies.
The cluster is an aggregrate 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.
Of all of the subclumps, Virgo A, formed by a mixture of elliptical, lenticular, and (usually) gas-poor spiral galaxies, is the dominant one, with a mass of approximately 1014 M☉, which is approximately an order of magnitude larger than the other two subclumps.
The three subgroups are in the process of merging to form a larger single cluster 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, 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. This strongly suggests the Virgo cluster is a dynamically young cluster that is still forming.
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.
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. Within the intracluster medium (ICM) are found a large number of intergalactic stars (up to 10% of the stars in the cluster), including some planetary nebulae. It is theorized that these were expelled from their home galaxies by interactions with other galaxies. The ICM also contains some globular clusters, possibly stripped off dwarf galaxies, and even at least one star formation region.
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:)
|Designation||Coordinates (Epoch 2000)||Apparent
|Messier 98||12 13.8||14 54||10.9||SBb||9.8′||150||184||Virgo A or N Cloud|
|NGC 4216||12 15.9||13 09||10.9||SBb||7.9′||120||459||Virgo A, N Cloud, or LVC.|
|Messier 99||12 18.8||14 25||10.4||Sc||5.4′||80||2735||Virgo A or N Cloud|
|NGC 4262||12 19.5||14 53||12.4||S0||1.9′||30||1683||Virgo A|
|NGC 4388||12 25.5||12 39||11.8||SAb||6.2′||85||2845||Virgo A|
|Messier 61||12 21.9||04 28||10.2||SBbc||6.2′||100||1911||S Cloud|
|Messier 100||12 22.9||15 49||10.1||SBbc||7.6′||115||1899||Virgo A|
|Messier 84||12 25.1||12 53||10.1||E1||6.0′||90||1239||Virgo A|
|Messier 85||12 25.4||18 11||10.0||S0||7.1′||105||1056||Virgo A|
|Messier 86||12 26.2||12 57||9.9||E3||10.2′||155||37||Virgo A or own subgroup.|
|NGC 4435||12 27.7||13 05||11.7||S0||3.0′||45||1111||Virgo A|
|NGC 4438||12 27.8||13 01||11.0||Sa||8.7′||130||404||Virgo A|
|NGC 4450||12 28.5||17 05||10.9||Sab||5.1′||80||2273||Virgo A|
|Messier 49||12 29.8||08 00||9.3||E2||9.8′||150||1204||Virgo B|
|Messier 87||12 30.8||12 23||9.6||E0–1||9.8′||150||1204||Virgo A|
|Messier 88||12 32.0||14 25||10.3||Sb||6.8′||100||2599||Virgo A|
|NGC 4526||12 32.0||07 42||10.6||S0||7.1′||105||931||Virgo B|
|NGC 4527||12 34.1||02 39||12.4||Sb||4.6′||69||1730||S Cloud|
|NGC 4536||12 34.4||02 11||11.1||SBbc||7.2′||115||2140||S Cloud|
|Messier 91||12 35.4||14 30||11.0||SBb||5.2′||80||803||Virgo A|
|NGC 4550||12 35.5||12 13||12.5||S0||3.2′||50||704||Virgo A|
|Messier 89||12 35.7||12 33||10.7||E0||5.0′||75||628||Virgo A|
|NGC 4567||12 36.5||11 15||12.1||Sbc||2.8′||40||2588||Virgo A|
|NGC 4568||12 36.6||11 14||11.7||Sbc||4.4′||65||2578||Virgo A|
|Messier 90||12 36.8||13 10||10.2||SBab||10.5′||160||87||Virgo A|
|NGC 4571||12 36.9||14 13||11.9||Sc||3.7′||55||659||Virgo A|
|Messier 58||12 37.7||11 49||10.6||SBb||5.6′||85||1839||Virgo A|
|Messier 59||12 42.9||11 39||10.8||E5||5.0′||75||751||Virgo A or Virgo E|
|Messier 60||12 43.7||11 33||9.8||E2||7.2′||110||1452||Virgo A, Virgo E, or Virgo C|
|NGC 4651||12 43.7||16 24||11.4||Sc||4.0′||60||1113|
|NGC 4654||12 43.9||13 08||11.1||SBc||5.0′||75||1349||Virgo 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.
Messier 61 (also known as M61 or NGC 4303) is an intermediate barred spiral galaxy in the Virgo Cluster of galaxies. It was discovered by Barnaba Oriani on May 5, 1779. This was six days before Charles Messier observed the same galaxy, but had mistaken it as a comet.Messier 86
Messier 86 (also known as M86 or NGC 4406) is an elliptical or lenticular galaxy in the constellation Virgo. It was discovered by Charles Messier in 1781. M86 lies in the heart of the Virgo Cluster of galaxies and forms a most conspicuous group with another large galaxy known as Messier 84. It displays the highest blue shift of all Messier objects, as it is approaching the Milky Way at 244 km/s. This is due to its falling towards the center of the Virgo cluster from the opposite side, which causes it to move in the direction of the Milky Way.Messier 86 is linked by several filaments of ionized gas to the severely disrupted spiral galaxy NGC 4438 and shows some gas and interstellar dust that may have been stripped of it like the one present in those filaments. It is also suffering ram-pressure stripping as it moves at high speed through Virgo's intracluster medium, losing its interstellar medium and leaving behind a very long trail of X ray-emitting hot gas that has been detected with the help of the Chandra space telescope.Messier 86 has a rich system of globular clusters, with a total number of around 3,800. Its halo also has a number of stellar streams interpreted as remmants of dwarf galaxies that have been disrupted and absorbed by this galaxy.Messier 89
Messier 89 (M89 for short, also known as NGC 4552) is an elliptical galaxy in the constellation Virgo. It was discovered by Charles Messier on March 18, 1781. M89 is a member of the Virgo Cluster of galaxies.Messier 90
Messier 90 (also known as M90 and NGC 4569) is an intermediate spiral galaxy exhibiting a weak inner ring structure about 60 million light-years away in the constellation Virgo. It was discovered by Charles Messier in 1781.Messier 99
Messier 99 or M99, also known as NGC 4254, is a grand design spiral galaxy in the northern constellation Coma Berenices approximately 15 megaparsecs (49 megalight-years) in distance from the Milky Way. It was discovered by Pierre Méchain on March 17, 1781. The discovery was then reported to Charles Messier, who included the object in the Messier Catalogue of comet-like objects. Messier 99 was one of the first galaxies in which a spiral pattern was seen. This pattern was first identified by Lord Rosse in the spring of 1846.This galaxy has a morphological classification of SA(s)c, indicating a pure spiral shape with loosely wound arms. It has a peculiar shape with one normal looking arm and an extended arm that is less tightly wound. The galaxy is inclined by 42° to the line-of-sight with a major axis position angle of 68°. Four supernovae have been observed in this galaxy: SN 1967H (type II), 1972Q, 1986I (type II), and 2014L (type Ic).A bridge of neutral hydrogen gas links NGC 4254 with VIRGOHI21, an HI region and a possible dark galaxy. The gravity from the latter may have distorted M99 and drawn out the gas bridge, as the two galaxy-sized objects may have had a close encounter before they went their separate ways. However, VIRGOHI21 may instead be tidal debris from an interaction with the lenticular galaxy NGC 4262 some 280 million years ago. It is expected that the drawn out arm will relax to match the normal arm once the encounter is over.
While not classified as a starburst galaxy, M99 has a star formation activity three times larger than other galaxies of similar Hubble type that may have been triggered by the encounter. M99 is likely entering the Virgo Cluster for the first time and is located at the periphery of the cluster at a projected separation of 3.7°, or around one megaparsec, from the cluster center at Messier 87. The galaxy is undergoing ram-pressure stripping as it moves through the intracluster medium.NGC 4207
NGC 4207 is a spiral galaxy located about 50 million light-years away in the constellation Virgo. The galaxy was discovered by astronomer Heinrich d'Arrest on March 23, 1865. NGC 4207 is a member of the Virgo Cluster.NGC 4388
NGC 4388 is an active spiral galaxy located in the Virgo Cluster. NGC 4388 is also considered to be one of the brightest galaxies in the Virgo Cluster due to its luminous nucleus.NGC 4461
NGC 4461 is a lenticular galaxy located about 50 million light-years away in the constellation of Virgo. It was discovered by astronomer William Herschel on April 12, 1784. NGC 4461 is a member of Markarian's Chain which is part of the Virgo Cluster.NGC 4482
NGC 4482 is a dwarf elliptical galaxy located about 60 million light-years away in the constellation Virgo. NGC 4482 was discovered by astronomer William Herschel on March 15, 1784. It was rediscovered by astronomer Arnold Schwassmann on September 6, 1900 and was listed as IC 3427. It is a member of the Virgo Cluster.NGC 4483
NGC 4483 is a barred lenticular galaxy located about 55 million light-years away in the constellation of Virgo. NGC 4483 was discovered by astronomer Heinrich d'Arrest on March 19, 1865. NGC 4483 is a member of the Virgo Cluster.NGC 4498
NGC 4498 is a barred spiral galaxy located about 50 million light-years away in the constellation Coma Berenices. NGC 4498 was discovered by astronomer William Herschel on March 21, 1784. NGC 4498 is a member of the Virgo Cluster.NGC 4503
NGC 4503 is a barred lenticular galaxy located around 41 to 74 million light-years away in the constellation Virgo. NGC 4503 was discovered by astronomer William Herschel on March 15, 1784. NGC 4503 is a member of the Virgo Cluster.NGC 4519
NGC 4519 is a barred spiral galaxy located about 70 million light-years away in the constellation Virgo. NGC 4519 was discovered by astronomer William Herschel on April 15, 1784. It has companion galaxy known as PGC 41706 and is a member of the Virgo Cluster.NGC 4528
NGC 4528 is a barred lenticular galaxy located about 50 million light-years away in the constellation Virgo. It was discovered by astronomer William Herschel on March 15, 1784. The galaxy is member of the Virgo Cluster.NGC 4544
NGC 4544 is an edge-on spiral galaxy located about 52 million light-years away in the constellation Virgo. NGC 4544 was discovered by astronomer Edward Swift on April 27, 1887. NGC 4544 is member of the Virgo Cluster.NGC 4578
NGC 4578 is a lenticular galaxy located about 55 million light-years away in the constellation Virgo. NGC 4578 was discovered by astronomer William Herschel on January 18, 1784 and is a member of the Virgo Cluster.NGC 4607
NGC 4607 is an edge-on spiral galaxy located about 56 million light-years away in the constellation Virgo. NGC 4607 was discovered by astronomer R. J. Mitchell on April 24, 1854. The galaxy is a member of the Virgo Cluster.NGC 4623
NGC 4623 is an edge-on lenticular or elliptical galaxy located about 54 million light-years away in the constellation of Virgo. NGC 4623 is classified as an E7, a rare type of "late" elliptical that represents the first stage of transition into a lenticular galaxy. NGC 4623 was discovered by astronomer William Herschel on April 13, 1784. NGC 4623 is a member of the Virgo Cluster.NGC 4639
NGC 4639 is a barred spiral galaxy located in the constellation Virgo. It lies over 70 million light-years away from planet Earth. Its core contains a massive black hole. NGC 4639 is also classified as a Seyfert galaxy. NGC 4639 is a member of the Virgo Cluster.
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