Virgo Supercluster

Last updated
Local Supercluster
Local supercluster-ly.jpg
Distances from the Local Group for selected groups and clusters within the Local Supercluster
Observation data (Epoch J2000)
Parent structure Laniakea Supercluster
Redshift Doppler shift
Binding mass ~1.48 × 1015 [1]   M☉
Luminosity (specify)3×1012 L☉ [1] (total)
Other designations
Virgo Supercluster (old), LSC, LS

The Local Supercluster (LSC or LS), or Virgo Supercluster is a formerly defined supercluster containing the Virgo Cluster and Local Group, which itself contains the Milky Way and Andromeda galaxies, as well as others. At least 100 galaxy groups and clusters are located within its diameter of 33 megaparsecs (110 million light-years). The Virgo Supercluster is one of about 10 million superclusters in the observable universe and is in the Pisces–Cetus Supercluster Complex, a galaxy filament.

Contents

A 2014 study indicates that the Local Supercluster is only a part of an even greater supercluster, Laniakea, a larger group centered on the Great Attractor, [2] thus subsuming the former Virgo Supercluster under Laniakea.

Background

Beginning with the first large sample of nebulae published by William and John Herschel in 1863, it was known that there is a marked excess of nebular fields in the constellation Virgo, near the north galactic pole. In the 1950s, French–American astronomer Gérard de Vaucouleurs was the first to argue that this excess represented a large-scale galaxy-like structure, coining the term "Local Supergalaxy" in 1953, which he changed to "Local Supercluster" (LSC [3] ) in 1958. Harlow Shapley, in his 1959 book Of Stars and Men, suggested the term Metagalaxy. [4]

Debate went on during the 1960s and 1970s as to whether the Local Supercluster (LS) was actually a structure or a chance alignment of galaxies. [5] The issue was resolved with the large redshift surveys of the late 1970s and early 1980s, which convincingly showed the flattened concentration of galaxies along the supergalactic plane. [6]

Structure

In a comprehensive 1982 paper, R. Brent Tully presented the conclusions of his research concerning the basic structure of the LS. It consists of two components: an appreciably flattened disk containing two thirds of the supercluster's luminous galaxies, and a roughly spherical halo containing the remaining third. [7] The disk itself is a thin (~1 Mpc) ellipsoid with a long axis / short axis ratio of at least 6 to 1, and possibly as high as 9 to 1. [8] Data released in June 2003 from the 5-year Two-degree-Field Galaxy Redshift Survey (2dF) has allowed astronomers to compare the LS to other superclusters. The LS represents a typical poor (that is, lacking a high density core) supercluster of rather small size. It has one rich galaxy cluster in the center, surrounded by filaments of galaxies and poor groups. [1]

The Local Group is located on the outskirts of the LS in a small filament extending from the Fornax Cluster to the Virgo Cluster. [6] The Virgo Supercluster's volume is roughly 7,000 times that of the Local Group, or 100 billion times that of the Milky Way.

Galaxy distribution

The number density of galaxies in the LS falls off with the square of the distance from its center near the Virgo Cluster, suggesting that this cluster is not randomly located. Overall, the vast majority of the luminous galaxies (less than absolute magnitude −13) are concentrated in a small number of clouds (groups of galaxy clusters). Ninety-eight percent can be found in the following 11 clouds, given in decreasing order of number of luminous galaxies: Canes Venatici, Virgo Cluster, Virgo II (southern extension), Leo II, Virgo III, Crater (NGC 3672), Leo I, Leo Minor (NGC 2841), Draco (NGC 5907), Antlia (NGC 2997), and NGC 5643.

Of the luminous galaxies located in the disk, one third are in the Virgo Cluster. The remainder are found in the Canes Venatici Cloud and Virgo II Cloud, plus the somewhat insignificant NGC 5643 Group.

The luminous galaxies in the halo are concentrated in a small number of clouds (94% in 7 clouds). This distribution indicates that "most of the volume of the supergalactic plane is a great void." [8] A helpful analogy that matches the observed distribution is that of soap bubbles. Flattish clusters and superclusters are found at the intersection of bubbles, which are large, roughly spherical (on the order of 20–60 Mpc in diameter) voids in space. [9] Long filamentary structures seem to predominate. An example of this is the Hydra–Centaurus Supercluster, the nearest supercluster to the Virgo Supercluster, which starts at a distance of roughly 30 Mpc and extends to 60 Mpc. [10]

Cosmology

Large-scale dynamics

Since the late 1980s it has been apparent that not only the Local Group, but all matter out to a distance of at least 50 Mpc is experiencing a bulk flow on the order of 600 km/s in the direction of the Norma Cluster (Abell 3627). [11] Lynden-Bell et al. (1988) dubbed the cause of this the "Great Attractor". The Great Attractor is now understood to be the center of mass of an even larger structure of galaxy clusters, dubbed "Laniakea", which includes the Virgo Supercluster (including the Local Group) as well as the Hydra-Centaurus Supercluster, the Pavo-Indus Supercluster, and the Fornax Group.

The Great Attractor, together with the entire supercluster, is found to be moving toward Shapley Supercluster, with center of Shapley Attractor. [12]

Dark matter

The LS has a total mass M ≈ 1015 M☉ and a total optical luminosity L ≈ 3×1012 L☉. [1] This yields a mass-to-light ratio of about 300 times that of the solar ratio (M☉/L☉ = 1), a figure that is consistent with results obtained for other superclusters. [13] [14] By comparison, the mass-to-light ratio for the Milky Way is 63.8 assuming a solar absolute magnitude of 4.83, [15] a Milky Way absolute magnitude of −20.9, [16] and a Milky Way mass of 1.25×1012 M☉. [17] These ratios are one of the main arguments in favor of the presence of large amounts of dark matter in the universe; if dark matter did not exist, much smaller mass-to-light ratios would be expected.

Maps

Map of the nearby universe within 100 million light-years from Earth, including a portion of the Southern Supercluster at the bottom left and the Virgo Supercluster on the right in supergalactic coordinates (click on feature names for more information) Virgosupercluster atlasoftheuniverse.gifNGC 5033 groupLeo I GroupNGC 6744 Group
Map of the nearby universe within 100 million light-years from Earth, including a portion of the Southern Supercluster at the bottom left and the Virgo Supercluster on the right in supergalactic coordinates (click on feature names for more information)
The nearest galaxy groups projected onto the supergalactic plane (click on feature names for more information) Nearest Groups of Galaxies atlasoftheuniverse.gif
The nearest galaxy groups projected onto the supergalactic plane (click on feature names for more information)

Diagrams

Location of Earth (9x1-English Annot-small).png
A diagram of our location in the observable universe. ( Alternative image.)

See also

Related Research Articles

<span class="mw-page-title-main">Local Group</span> Group of galaxies that includes the Milky Way

The Local Group is the galaxy group that includes the Milky Way, where Earth is located. It has a total diameter of roughly 3 megaparsecs (10 million light-years; 9×1019 kilometres), and a total mass of the order of 2×1012 solar masses (4×1042 kg). It consists of two collections of galaxies in a "dumbbell" shape; the Milky Way and its satellites form one lobe, and the Andromeda Galaxy and its satellites constitute the other. The two collections are separated by about 800 kiloparsecs (3×10^6 ly; 2×1019 km) and are moving toward one another with a velocity of 123 km/s. The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies.

<span class="mw-page-title-main">Supercluster</span> Large group of smaller galaxy clusters or galaxy groups

A supercluster is a large group of smaller galaxy clusters or galaxy groups; they are among the largest known structures in the universe. The Milky Way is part of the Local Group galaxy group, which in turn is part of the Virgo Supercluster, which is part of the Laniakea Supercluster, which is part of the Pisces–Cetus Supercluster Complex. The large size and low density of superclusters means that they, unlike clusters, expand with the Hubble expansion. The number of superclusters in the observable universe is estimated to be 10 million.

<span class="mw-page-title-main">Timeline of knowledge about galaxies, clusters of galaxies, and large-scale structure</span>

The following is a timeline of galaxies, clusters of galaxies, and large-scale structure of the universe.

<span class="mw-page-title-main">Great Attractor</span> Region of overdensity of galaxies within the local supercluster

The Great Attractor is a region of gravitational attraction in intergalactic space and the apparent central gravitational point of the Laniakea Supercluster of galaxies that includes the Milky Way galaxy, as well as about 100,000 other 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">Hydra–Centaurus Supercluster</span> Former galaxy supercluster

The Hydra–Centaurus Supercluster, or the Hydra and Centaurus Superclusters, was a previously defined supercluster in two parts, which prior to the identification of Laniakea Supercluster in 2014 is the closest neighbour of the former Virgo Supercluster. Its center is located about 39 Mpc (127 Mly) away, with it extending to a maximum distance of around 69 Mpc (225 Mly).

<span class="mw-page-title-main">Shapley Supercluster</span> Largest concentration of galaxies in our local universe

The Shapley Supercluster or Shapley Concentration is the largest concentration of galaxies in our nearby universe that forms a gravitationally interacting unit, thereby pulling itself together instead of expanding with the universe. It appears as a striking overdensity in the distribution of galaxies in the constellation of Centaurus. It is 650 million light-years away (z=0.046).

<span class="mw-page-title-main">NGC 5170</span> Edge-on spiral galaxy in the constellation Virgo

NGC 5170 is a large, nearby, edge-on spiral galaxy in the equatorial constellation of Virgo. It was discovered on February 7, 1785 by William Herschel. This galaxy is located at a distance of 83.5 million light years and is receding at a heliocentric radial velocity of 1,502 km/s. 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.

<span class="mw-page-title-main">Pavo–Indus Supercluster</span> Neighboring supercluster in the constellations Pavo, Indus and Telescopium

The Pavo–Indus Supercluster is a neighboring supercluster located about 60–70 Mpc (196–228 Mly) away in the constellations of Pavo, Indus, and Telescopium. The supercluster contains three main clusters, Abell 3656, Abell 3698, and Abell 3742.

<span class="mw-page-title-main">Galaxy filament</span> Largest structures in the universe, made of galaxies

In cosmology, galaxy filaments are the largest known structures in the universe, consisting of walls of galactic superclusters. These massive, thread-like formations can commonly reach 50/h to 80/h megaparsecs —with the largest found to date being the Hercules-Corona Borealis Great Wall at around 3 gigaparsecs (9.8 Gly) in length—and form the boundaries between voids. Due to the accelerating expansion of the universe, the individual clusters of gravitationally bound galaxies that make up galaxy filaments are moving away from each other at an accelerated rate; in the far future they will dissolve.

The Pisces–Cetus Supercluster Complex is a galaxy filament. It includes the Laniakea Supercluster which contains the Virgo Supercluster lobe which in turn contains the Local Group, the galaxy cluster that includes the Milky Way. This filament is adjacent to the Perseus–Pegasus Filament. Astronomer R. Brent Tully of the University of Hawaii's Institute of Astronomy identified the Complex in 1987.

<span class="mw-page-title-main">Local Sheet</span> Nearby extragalactic region of space

The Local Sheet in astronomy is a nearby extragalactic region of space where the Milky Way, the members of the Local Group and other galaxies share a similar peculiar velocity. This region lies within a radius of about 7 Mpc (23 Mly), 0.46 Mpc (1.5 Mly) thick, and galaxies beyond that distance show markedly different velocities. The Local Group has only a relatively small peculiar velocity of 66 km⋅s−1 with respect to the Local Sheet. Typical velocity dispersion of galaxies is only 40 km⋅s−1 in the radial direction. Nearly all nearby bright galaxies belong to the Local Sheet. The Local Sheet is part of the Local Volume and is in the Virgo Supercluster. The Local Sheet forms a wall of galaxies delineating one boundary of the Local Void.

<span class="mw-page-title-main">Laniakea Supercluster</span> Galaxy supercluster that is home to the Milky Way Galaxy and many more galaxies

The Laniakea Supercluster or the Local Supercluster is the galaxy supercluster that is home to the Milky Way and approximately 100,000 other nearby galaxies.

<span class="mw-page-title-main">Southern Supercluster</span> Closest neighboring galaxy supercluster

The Southern Supercluster is a nearby supercluster located around 19.5 Mpc (63.6 Mly) in the constellations of Cetus, Fornax, Eridanus, Horologium, and Dorado. It was first identified in 1953 by Gérard de Vaucouleurs.

<span class="mw-page-title-main">ESO 444-46</span> Galaxy in the constellation Centaurus

ESO 444-46 is a class E4 supergiant elliptical galaxy; the dominant and brightest member of the Abell 3558 galaxy cluster around 195 megaparsecs away in the constellation Centaurus. It lies within the core of the massive Shapley Supercluster, one of the closest neighboring superclusters. It is one of the largest galaxies in the local universe, and possibly contains one of the most massive black holes known. The black hole's mass is very uncertain, with estimates ranging from as low as 501 million M☉, to as high as 77.6 billion M☉.

<span class="mw-page-title-main">NGC 4636</span> Galaxy in the constellation Virgo

NGC 4636 is an elliptical galaxy located in the constellation Virgo. It is a member of the NGC 4753 Group of galaxies, which 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 is located at a distance of about 55 million light years from Earth, which, given its apparent dimensions, means that NGC 4636 is about 105,000 light years across.

<span class="mw-page-title-main">NGC 5846</span> Galaxy in the constellation Virgo

NGC 5846 is an elliptical galaxy located in the constellation Virgo. It is located at a distance of circa 90 million light years from Earth, which, given its apparent dimensions, means that NGC 5846 is about 110,000 light years across. It was discovered by William Herschel on February 24, 1786. It lies near 110 Virginis and is part of the Herschel 400 Catalogue. It is a member of the NGC 5846 Group of galaxies, itself one of the Virgo III Groups strung out to the east of the Virgo Supercluster of galaxies.

The Telescopium−Grus Cloud is a galaxy filament in the constellations of Pavo, Indus, and Telescopium. It was first defined by astronomer Brent Tully in his book The Nearby Galaxies Atlas and its companion book The Nearby Galaxies Catalog.

<span class="mw-page-title-main">NGC 4324</span> Galaxy in the constellation of Virgo

NGC 4324 is a lenticular galaxy located about 85 million light-years away in the constellation Virgo. It was discovered by astronomer Heinrich d'Arrest on March 4, 1862. NGC 4324 has a stellar mass of 5.62 × 1010M☉, and a baryonic mass of 5.88 × 1010M☉. The galaxy's total mass is around 5.25 × 1011M☉. NGC 4324 is notable for having a ring of star formation surrounding its nucleus. It was considered a member of the Virgo II Groups until 1999, when its distance was recalculated and it was placed in the Virgo W Group.

<span class="mw-page-title-main">ESO 383-76</span> Galaxy in the constellation Centaurus

ESO 383-76 is an elongated, X-ray luminous supergiant elliptical galaxy, residing as the dominant, brightest cluster galaxy (BCG) of the Abell 3571 galaxy cluster, the sixth-brightest in the sky at X-ray wavelengths. It is located at the distance of 200.6 megaparsecs from Earth, and is possibly a member of the large Shapley Supercluster. With a diameter of about 540.9 kiloparsecs, it is one of the largest galaxies known. It also contains a supermassive black hole, one of the most massive known with mass estimates varying from 2 billion M☉ to 28 billion M☉.

References

  1. 1 2 3 4 Einasto, M.; et al. (December 2007). "The richest superclusters. I. Morphology". Astronomy and Astrophysics. 476 (2): 697–711. arXiv: 0706.1122 . Bibcode:2007A&A...476..697E. doi:10.1051/0004-6361:20078037. S2CID   15004251.
  2. ↑ R. Brent Tully; Hélène Courtois; Yehuda Hoffman; Daniel Pomarède (2 September 2014). "The Laniakea supercluster of galaxies". Nature. 513 (7516) (published 4 September 2014): 71–73. arXiv: 1409.0880 . Bibcode:2014Natur.513...71T. doi:10.1038/nature13674. PMID   25186900. S2CID   205240232.
  3. ↑ cfa.harvard.edu, The Geometry of the Local Supercluster, John P. Huchra, 2007 (accessed 12-12-2008)
  4. ↑ Shapley, Harlow Of Stars and Men (1959)
  5. ↑ de Vaucouleurs, G. (March 1981). "The Local Supercluster of Galaxies". Bulletin of the Astronomical Society of India. 9: 6 (see note). Bibcode:1981BASI....9....1D.
  6. 1 2 Klypin, Anatoly; et al. (October 2003). "Constrained Simulations of the Real Universe: The Local Supercluster". The Astrophysical Journal. 596 (1): 19–33. arXiv: astro-ph/0107104 . Bibcode:2003ApJ...596...19K. doi:10.1086/377574. S2CID   1830859.
  7. ↑ Hu, F. X.; et al. (April 2006). "Orientation of Galaxies in the Local Supercluster: A Review". Astrophysics and Space Science. 302 (1–4): 43–59. arXiv: astro-ph/0508669 . Bibcode:2006Ap&SS.302...43H. doi:10.1007/s10509-005-9006-7. S2CID   18837475.
  8. 1 2 Tully, R. B. (15 Jun 1982). "The Local Supercluster". Astrophysical Journal. 257 (1): 389–422. Bibcode:1982ApJ...257..389T. doi: 10.1086/159999 .
  9. ↑ Carroll, Bradley; Ostlie, Dale (1996). An Introduction to Modern Astrophysics. New York: Addison-Wesley. p. 1136. ISBN   0-201-54730-9.
  10. ↑ Fairall, A. P.; Vettolani, G.; Chincarini, G. (May 1989). "A wide angle redshift survey of the Hydra-Centaurus region". Astronomy and Astrophysics Supplement Series. 78 (2): 270. Bibcode:1989A&AS...78..269F. ISSN   0365-0138.
  11. ↑ Plionis, Manolis; Valdarnini, Riccardo (March 1991). "Evidence for large-scale structure on scales about 300/h MPC". Monthly Notices of the Royal Astronomical Society. 249: 46–61. Bibcode:1991MNRAS.249...46P. doi: 10.1093/mnras/249.1.46 .
  12. ↑ "What is the Great Attractor?". 14 July 2014.
  13. ↑ Small, Todd A.; et al. (Jan 1998). "The Norris Survey of the Corona Borealis Supercluster. III. Structure and Mass of the Supercluster". Astrophysical Journal. 492 (1): 45–56. arXiv: astro-ph/9708153 . Bibcode:1998ApJ...492...45S. doi:10.1086/305037. S2CID   119451873.
  14. ↑ Heymans, Catherine; et al. (April 2008). "The dark matter environment of the A901 abell A901/902 supercluster: a weak lensing analysis of the HST STAGES survey". Monthly Notices of the Royal Astronomical Society . 385 (3): 1431–1442. arXiv: 0801.1156 . Bibcode:2008MNRAS.385.1431H. doi: 10.1111/j.1365-2966.2008.12919.x . S2CID   59057342.
  15. ↑ Williams, D. R. (2004). "Sun Fact Sheet". NASA . Retrieved 2012-03-17.
  16. ↑ Jerry Coffey. "Absolute Magnitude" . Retrieved 2010-04-09.
  17. ↑ McMillan, Paul J. (July 2011), "Mass models of the Milky Way", Monthly Notices of the Royal Astronomical Society, 414 (3): 2446–2457, arXiv: 1102.4340 , Bibcode:2011MNRAS.414.2446M, doi: 10.1111/j.1365-2966.2011.18564.x , S2CID   119100616

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