The Virgo Supercluster (Virgo SC) or the Local Supercluster (LSC or LS) is a mass concentration of

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...

containing the

Virgo Cluster The Virgo Cluster is a large cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the constellation Virgo. Comprising approximately 1,300 (and possibly up to 2,000) member galaxies, the cluster forms the heart of the l ...

and

Local Group The Local Group is the galaxy group that includes the Milky Way. It has a total diameter of roughly , and a total mass of the order of . It consists of two collections of galaxies in a "dumbbell" shape: the Milky Way and its satellites form ...

, which itself contains the

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked ey ...

and Andromeda galaxies, as well as others. At least 100 galaxy groups and clusters are located within its diameter of 33

megaparsecs The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (au), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, a ...

(110 million

light-years A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 101 ...

). The Virgo SC is one of about 10 million superclusters in the

observable universe The observable universe is a ball-shaped region of the universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time, because the electromagnetic radiation from these obj ...

and is in the Pisces–Cetus Supercluster Complex, a

galaxy filament In cosmology, galaxy filaments (subtypes: supercluster complexes, galaxy walls, and galaxy sheets) Boris V. Komberg, Andrey V. Kravtsov, Vladimir N. Lukash; "The search and investigation of the Large Groups of Quasars" ; ;R.G. Clowes; "Large Qu ...

. A 2014 study indicates that the Virgo Supercluster is only a lobe of an even greater supercluster, Laniakea, a larger, competing referent of the term Local Supercluster centered on the

Great Attractor The Great Attractor is a gravitational anomaly in intergalactic space and the apparent central gravitational point of the Laniakea Supercluster. The observed anomalies suggest a localized concentration of mass millions of times more massive tha ...

Background

Beginning with the first large sample of

nebula A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regio ...

e published by

William William is a masculine given name of Norman French origin.Hanks, Hardcastle and Hodges, ''Oxford Dictionary of First Names'', Oxford University Press, 2nd edition, , p. 276. It became very popular in the English language after the Norman conq ...

and

John Herschel Sir John Frederick William Herschel, 1st Baronet (; 7 March 1792 – 11 May 1871) was an English polymath active as a mathematician, astronomer, chemist, inventor, experimental photographer who invented the blueprint and did botanic ...

in 1863, it was known that there is a marked excess of nebular fields in the constellation

Virgo Virgo may refer to: * Virgo (astrology), the sixth astrological sign of the zodiac * Virgo (constellation), a constellation * Virgo Cluster, a cluster of galaxies in the constellation Virgo * Virgo Stellar Stream, remains of a dwarf galaxy *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) in 1958. ( Harlow Shapley, in his 1959 book ''Of Stars and Men'', suggested the term ''Metagalaxy''.) 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. 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.

Structure

In a comprehensive 1982 paper,

R. Brent Tully Richard Brent Tully (born March 9, 1943) is a Canadian-born American astronomer at the Institute for Astronomy in Honolulu, Hawaii. Born in Toronto, Ontario, and raised in Vancouver, British Columbia, Tully's specialty is the astrophysics of gal ...

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 one-third. The disk itself is a thin (~1

Mpc MPC, Mpc or mpc may refer to: Astronomy * Megaparsec (Mpc), unit of length used in astronomy * Minor Planet Center, Smithsonian Astrophysical Observatory ** ''Minor Planet Circulars'' (MPC, M.P.C. or MPCs), astronomical publication from the Minor ...

) ellipsoid with a long axis / short axis ratio of at least 6 to 1, and possibly as high as 9 to 1. 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. The

is located on the outskirts of the LS in a small filament extending from the

Fornax Cluster The Fornax Cluster is a cluster of galaxies lying at a distance of 19 megaparsecs (62 million light-years). It has an estimated mass of solar masses, making it the second richest galaxy cluster within 100 million light-years, after the conside ...

to the

. The Virgo Supercluster's volume is very approximately 7000 times that of the Local Group or 100 billion times that of the Milky Way.

Galaxy distribution

The

number density The number density (symbol: ''n'' or ''ρ''N) is an intensive quantity used to describe the degree of concentration of countable objects (particles, molecules, phonons, cells, galaxies, etc.) in physical space: three-dimensional volumetric number ...

of galaxies in the LS falls off with the square of the distance from its center near the

, suggesting that this cluster is not randomly located. Overall, the vast majority of the luminous galaxies (less than

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it we ...

−13) are concentrated in a small number of

clouds In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals ma ...

(groups of

galaxy cluster A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. They are the second-la ...

s). 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 NGC commonly refers to: * New General Catalogue of Nebulae and Clusters of Stars, a catalogue of deep sky objects in astronomy NGC may also refer to: Companies * NGC Corporation, name of US electric company Dynegy, Inc. from 1995 to 1998 * Nat ...

), Leo I, Leo Minor (

NGC 2841 NGC 2841 is an unbarred spiral galaxy in the northern circumpolar constellation of Ursa Major. It was discovered on 9 March 1788 by German-born astronomer William Herschel. J. L. E. Dreyer, the author of the ''New General Catalogue'', described ...

), Draco (

NGC 5907 NGC 5907 (also known as Knife Edge Galaxy or Splinter Galaxy) is a spiral galaxy located approximately 50 million light years from Earth. It has an anomalously low metallicity and few detectable giant stars, being apparently composed almost entir ...

), Antlia ( NGC 2997), and

NGC 5643 NGC 5643 is an intermediate spiral galaxy in the constellation Lupus. Based on the tip of the red-giant branch distance indicator, it is located at a distance of about 40 million light-years (12.5 megaparsecs). NGC 5643 has an active galactic n ...

. Of the luminous galaxies located in the disk, one third are in the Virgo Cluster, while 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 also 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." A helpful analogy that matches the observed distribution is that of soap bubbles. Flattish clusters and

superclusters 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 contains more than 54 galaxies), which in turn ...

are found at the intersection of bubbles, which are large, roughly spherical (on the order of 20–60

in diameter) voids in space. Long filamentary structures seem to predominate. An example of this is the Hydra–Centaurus Supercluster, the nearest supercluster to the LS, which starts at a distance of roughly 30 Mpc and extends to 60 Mpc.

Cosmology

Large-scale dynamics

Since the late 1980s it has been apparent that not only the

, but all matter out to a distance of at least 50

is experiencing a bulk flow on the order of 600 km/s in the direction of the Norma Cluster (Abell 3627). Lynden-Bell et al. (1988) dubbed the cause of this the "

". 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 The Shapley attractor is an attractor located about the Shapley Supercluster. It is opposed to the Dipole Repeller, in the CMB dipole of local galactic flow. It is thought to be the composite contributions of the Shapley Concentration and the G ...

Dark matter

The LS has a total mass ''M'' ≈ 10¹⁵ and a total optical luminosity ''L'' ≈ 3 . This yields a mass-to-light ratio of about 300 times that of the solar ratio (/ = 1), a figure that is consistent with results obtained for other superclusters. By comparison, the mass-to-light ratio for the

is 63.8 assuming a solar

of 4.83, a Milky Way absolute magnitude of −20.9, and a Milky Way mass of . These ratios are one of the main arguments in favor of the presence of large amounts of

dark matter Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not ab ...

in the universe; if dark matter did not exist, much smaller mass-to-light ratios would be expected.

Maps

File:Virgosupercluster atlasoftheuniverse.gif, frame, center, 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) circle 473 220 33

circle 339 230 16 Centaurus A/M83 Group circle 349 252 15

M81 group The M81 Group is a galaxy group in the constellations Ursa Major and Camelopardalis that includes the galaxies Messier 81 and Messier 82, as well as several other galaxies with high apparent brightnesses. The approximate center of the group ...

circle 326 264 15 Maffei Group circle 289 292 20

NGC 1023 Group The NGC 1023 group is a group of galaxies about 20.6 million light-years away from Earth. It is a group in the Local Supercluster along with the Local Group. Members * Probable (dwarfs): DDO 024, DDO 025. * Possible members: NGC 672 N ...

circle 370 236 13 M101 group circle 347 299 20 NGC 2997 Group circle 405 238 20 Canes Venatici I Group circle 426 203 19 NGC 5033 group rect 445 247 508 276

Ursa Major Cluster The Ursa Major Cluster (Ursa Major I Cluster, UMa I ClG) is a spiral-rich galaxy cluster of the Virgo Supercluster. Some of its largest members are NGC 3631, NGC 3953, M109 on North ( M109 Group) and NGC 3726, NGC 3938, NGC 4051 on South. Th ...

circle 391 270 18 Leo I Group circle 277 197 25 NGC 6744 Group circle 236 314 22 Dorado Group circle 518 87 40

Virgo III Groups The Virgo III Groups, or Virgo III Cloud, are a series of at least 75 galactic clusters and individual galaxies stretching approximately off the eastern edge of the Virgo Supercluster. Parts of it are in the constellations Virgo, Libra, and Se ...

circle 526 225 20 NGC 4697 circle 546 331 34

Leo II Groups The Leo II Groups, or Leo II Cloud, are a series of at least 110 galactic clusters and individual galaxies stretching approximately 30 Mly (9.2 Mpc) off the right edge of the Virgo Supercluster. It is located approximately 65 Mly (20 Mpc) to 95 M ...

circle 165 194 27

NGC 7582 NGC 7582 is a spiral galaxy of the Hubble type SB(s)ab in the constellation Grus. It has an angular size of 5.0' × 2.1' and an apparent magnitude of 11.37. It is about 70 million light years away from Earth and has a diameter of about 100,000 l ...

poly 180 356 178 325 252 345 242 378

poly 176 357 239 379 214 413 162 381 Eridanus Cluster rect 295 213 324 239

rect 252 235 304 257 Sculptor Group desc bottom-left File:Nearest Groups of Galaxies atlasoftheuniverse.gif, frame, center, The nearest galaxy groups projected onto the supergalactic plane (click on feature names for more information) circle 333 283 20 NGC 55 rect 399 299 419 325

circle 385 294 14

Large Magellanic Cloud The Large Magellanic Cloud (LMC), or Nubecula Major, is a satellite galaxy of the Milky Way. At a distance of around 50 kiloparsecs (≈160,000 light-years), the LMC is the second- or third-closest galaxy to the Milky Way, after the ...

circle 429 267 20

NGC 3109 NGC 3109 is a small barred Magellanic type spiral or irregular galaxy around 4.34 Mly away in the direction of the constellation of Hydra. NGC 3109 is believed to be tidally interacting with the dwarf elliptical galaxy Antlia Dwarf. It was disc ...

circle 395 338 16 Messier 31 circle 365 335 15 Messier 33 circle 278 311 20 NGC 247 circle 388 119 28

Circinus Galaxy The Circinus Galaxy (ESO 97-G13) is a Seyfert galaxy in the constellation of Circinus. It is located 4 degrees below the Galactic plane, and, at a distance of , is one of the closest major galaxies to the Milky Way. The galaxy is undergoing t ...

circle 456 124 17

NGC 5128 Centaurus A (also known as NGC 5128 or Caldwell 77) 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 d ...

circle 494 161 20 NGC 5253 poly 475 149 500 133 483 113 463 137

NGC 5102 NGC 5102, also known as Iota's Ghost, is a lenticular galaxy in the Centaurus A/M83 Group of galaxies. It was discovered by John Herschel in 1835. Distance measurements At least two techniques have been used to measure the distance to NGC 5102. ...

circle 440 165 28 NGC 5128 Group circle 368 206 27

IC 4662 IC 4662, also known as ESO 102-14 is an irregular galaxy located in the constellation Pavo (constellation), Pavo 7.96 million light years away. It was discovered by Robert Thorbun Ayton Innes in 1901. It has a diameter of 7000 light years and ...

circle 520 105 20 Messier 83 rect 699 183 774 265

circle 433 65 22 ESO 274-01 circle 266 177 22 NGC 1313 circle 214 255 20 NGC 625 circle 235 282 16 NGC 7793 rect 435 80 472 107

NGC 4945 NGC 4945 (also known as Caldwell 83) is a barred spiral galaxy in the constellation Centaurus, visible near the star Xi Centauri. The galaxy was discovered by James Dunlop in 1826 and is thought to be similar to the Milky Way Galaxy, although ...

circle 184 301 20 NGC 45 circle 217 311 17

NGC 253 The Sculptor Galaxy (also known as the Silver Coin, Silver Dollar Galaxy, NGC 253, or Caldwell 65) is an intermediate spiral galaxy in the constellation Sculptor (constellation), Sculptor. The Sculptor Galaxy is a starburst galaxy, which means t ...

circle 265 260 22 Sculptor Group rect 368 268 412 284

circle 409 379 25 NGC 1569 circle 296 280 17 NGC 300 circle 424 418 20 IC 342 rect 383 429 415 451 Maffei Group circle 325 442 20 NGC 404 circle 272 508 20

NGC 784 NGC 784 is a barred spiral galaxy about 16.0 Mly away in the constellation Triangulum. NGC 784 is located within the Virgo Supercluster The Virgo Supercluster (Virgo SC) or the Local Supercluster (LSC or LS) is a mass concentration of galax ...

circle 397 510 20

Maffei I Maffei 1 is a massive elliptical galaxy in the constellation Cassiopeia. Once believed to be a member of the Local Group of galaxies, it is now known to belong to a separate group, the IC 342/Maffei Group. It was named after Paolo Maffei, wh ...

rect 353 456 413 478

Maffei II Maffei 2 is an intermediate spiral galaxy about 1 E23 m, 10 million light-years away in the constellation Cassiopeia (constellation), Cassiopeia. Maffei 2 and Maffei 1 were both discovered by Paolo Maffei in 1968 from their infrared emission. M ...

rect 371 526 434 553

Dwingeloo 1 Dwingeloo 1 is a barred spiral galaxy about 10 million light-years away from the Earth, in the constellation Cassiopeia. It lies in the Zone of Avoidance and is heavily obscured by the Milky Way. The size and mass of Dwingeloo 1 are comparab ...

circle 444 481 22 NGC 1560 rect 510 417 537 434 Messier 81 rect 527 433 578 443 IC 2574 rect 500 434 515 450 Messier 82 poly 516 434 521 456 554 456 552 447 533 445 523 435

NGC 3077 NGC 3077 is a small disrupted elliptical galaxy, a member of the M81 Group, which is located in the northern constellation Ursa Major. Despite being similar to an elliptical galaxy in appearance, it is peculiar for two reasons. First, it shows w ...

circle 549 476 18

NGC 2976 NGC 2976 is a peculiar dwarf galaxy in the northern circumpolar constellation of Ursa Major. It was discovered by German-born astronomer William Herschel on November 8, 1801, and catalogued as H I.285. J. L. E. Dreyer described it as, "bright ...

circle 604 440 22

NGC 4605 NGC 4605 is a dwarf barred spiral galaxy in the constellation Ursa Major, located at a distance of from the Milky Way. Physically it is similar in size and in B-band absolute magnitude to the Large Magellanic Cloud. It is a member of the M81 ...

circle 513 479 19 NGC 6503 circle 583 410 13 NGC 5204 circle 559 389 16 NGC 3738 circle 512 401 14 NGC 4236 rect 452 442 485 461

NGC 2366 NGC 2366 is a Magellanic Catalogue of Stars, Magellanic barred irregular galaxy, barred irregular dwarf galaxy located in the constellation Camelopardalis. There has been confusion about the various components of NGC 2366 and its neighbouring ...

rect 451 420 484 440 NGC 2403 rect 485 433 502 465 NGC 4305 circle 659 382 20 NGC 5023 rect 634 344 658 364 Messier 94 circle 618 355 15 NGC 4244 circle 594 337 13 NGC 4214 circle 577 361 19

NGC 4449 NGC 4449, also known as Caldwell 21, is an irregular Magellanic type galaxy in the constellation Canes Venatici, being located about 13 million light-years away. It is part of the M94 Group or Canes Venatici I Group that is relatively close t ...

circle 615 319 17 NGC 4395 rect 591 280 640 304 Canes I Group poly 528 393 542 392 558 411 525 414

M81 Group The M81 Group is a galaxy group in the constellations Ursa Major and Camelopardalis that includes the galaxies Messier 81 and Messier 82, as well as several other galaxies with high apparent brightnesses. The approximate center of the group ...

desc bottom-left

Diagrams

References

External links

The Atlas of the Universe
a website created by astrophysicist Richard Powell that shows maps of our local universe on a number of different scales (similar to above maps). {{Portal bar, Stars, Spaceflight, Solar System, Science Galaxy superclusters