Shapley Supercluster

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Shapley Supercluster
Galaxies in the Shapley Supercluster - Flickr - geckzilla.png
Galaxies in the Shapley Supercluster
Observation data (Epoch J2000)
Constellation(s) Centaurus
Right ascension 13h 25m [1]
Declination −30° 0′ 0″ [1]
Distance 200  Mpc (652  Mly)
Other designations
Shapley Concentration, SCl 124
See also: Galaxy group, Galaxy cluster, List of galaxy groups and clusters

The Shapley Supercluster or Shapley Concentration (SCl 124) 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).

Contents

History

In 1930, [2] Harlow Shapley and his colleagues at the Harvard College Observatory started a survey of galaxies in the southern sky, using photographic plates obtained at the 24-inch Bruce telescope at Bloemfontein, South Africa. By 1932, Shapley reported the discovery of 76,000 galaxies brighter than 18th apparent magnitude in a third of the southern sky, based on galaxy counts from his plates. Some of this data was later published as part of the Harvard galaxy counts, intended to map galactic obscuration and to find the space density of galaxies.

In this catalog, Shapley could see most of the 'Coma-Virgo cloud' (now known to be a superposition of the Coma Supercluster and the Virgo Supercluster), but found a 'cloud' in the constellation of Centaurus to be the most striking concentration of galaxies. He found it particularly interesting because of its "great linear dimension, the numerous population and distinctly elongated form". This can be identified with what we now know as the core of the Shapley Supercluster. Shapley estimated the distance to this cloud to be 14 times that to the Virgo Cluster, from the average diameters of the galaxies. This would place the Shapley Supercluster at a distance of 231 Mpc, based on the current estimate of the distance to Virgo.

In recent times, the Shapley Supercluster was named by Somak Raychaudhury, [3] from a survey of galaxies from UK Schmidt Telescope Sky survey plates, using the Automated Plate Measuring Facility (APM) at the University of Cambridge in England. In this paper, the supercluster was named after Harlow Shapley, in recognition of his pioneering survey of galaxies in which this concentration of galaxies was first seen. Around the same time, Roberto Scaramella and co-workers had also noticed the Shapley Supercluster in the Abell catalogue of clusters of galaxies: they had named it the Alpha concentration. [4]

A map of the Shapley Supercluster Shapley.gif
A map of the Shapley Supercluster

Current interest

The Shapley Supercluster lies very close to the direction in which the Local Group of galaxies (including our galaxy) is moving with respect to the cosmic microwave background (CMB) frame of reference. This has led many to speculate that the Shapley Supercluster may be one of the major causes of our galaxy's peculiar motion—the Great Attractor may be another—and has led to a surge of interest in this supercluster. It has been found that the Great Attractor and all the galaxies in our region of the universe (including our galaxy, the Milky Way) are moving toward the Shapley Supercluster. [5]

In 2017 it was proposed that the movement towards attractors like the Shapley Attractor in the supercluster creates a relative movement away from underdense areas, that may be visualized as a virtual repeller. This approach enables new ways of understanding and modelling variations in galactic movements. The nearest large underdense area has been labelled the dipole repeller. [6]

See also

Related Research Articles

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

<span class="mw-page-title-main">Virgo Supercluster</span> Galactic supercluster containing the Virgo Cluster

The Virgo Supercluster or the Local Supercluster is a mass concentration of galaxies 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. The Virgo SC is one of about 10 million superclusters in the observable universe and is in the Pisces–Cetus Supercluster Complex, a galaxy filament.

<span class="mw-page-title-main">Great Attractor</span> Apparent gravitational anomaly in the local supercluster

The Great Attractor is a purported gravitational attraction in intergalactic space and the apparent central gravitational point of the Laniakea Supercluster of galaxies. This supercluster contains the Milky Way galaxy, as well as about 100,000 other galaxies.

<span class="mw-page-title-main">Supergalactic coordinate system</span>

The supergalactic plane is part of a reference frame for the supercluster of galaxies that contains the Milky Way galaxy.

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

The Hydra–Centaurus Supercluster, or the Hydra and Centaurus Superclusters, is a supercluster in two parts, the closest neighbour of Virgo Supercluster. It is located about 39 Mpc (127 Mly) away.

<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">Somak Raychaudhury</span> Indian astrophysicist

Somak Raychaudhury is an Indian astrophysicist. He is the Vice-Chancellor at Ashoka University and was the Director of the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune. He is on leave from Presidency University, Kolkata, India, where he is a Professor of Physics, and is also affiliated to the University of Birmingham, United Kingdom. He is known for his work on stellar mass black holes and supermassive black holes. His significant contributions include those in the fields of gravitational lensing, galaxy dynamics and large-scale motions in the Universe, including the Great Attractor.

<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.

<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 is the galaxy supercluster that is home to the Milky Way and approximately 100,000 other nearby galaxies.

The Shapley attractor is an attractor located about the Shapley Supercluster.

<span class="mw-page-title-main">Dipole repeller</span> Center of effective repulsion in the large-scale flow of galaxies near the Milky Way

The dipole repeller is a center of effective repulsion in the large-scale flow of galaxies in the neighborhood of the Milky Way, first detected in 2017. It is thought to represent a large supervoid, the Dipole Repeller Void.

<span class="mw-page-title-main">Saraswati Supercluster</span> Supercluster of galaxies in the Pisces constellation

The Saraswati Supercluster is a massive galaxy supercluster about 1.2 gigaparsecs (4 billion light years) away within the Stripe 82 region of SDSS, in the direction of the constellation Pisces. It is one of the largest structures found in the universe, with a major axis in diameter of about 200 Mpc (652 million light years). It consists of at least 43 galaxy clusters, and has the mass of 2 × 1016 M☉, forming a galaxy filament.

<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">Hélène Courtois</span> French astrophysicist

Hélène Courtois is a French astrophysicist specialising in cosmography. She is a professor at the University of Lyon 1 and has been a chevalier of the Ordre des Palmes Académiques since 2015.

<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 640 million light-years 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☉.

Daniel Pomarède is a staff scientist at the Institute of Research into the Fundamental Laws of the Universe, CEA Paris-Saclay University. He co-discovered Laniakea, our home supercluster of galaxies, and Ho'oleilana, a spherical shell-like structure 1 billion light-years in diameter found in the distribution of galaxies, possibly the remnant of a Baryon Acoustic Oscillation. Specialized in data visualization and cosmography, a branch of cosmology dedicated to mapping the Universe, he also co-authored the discoveries of the Dipole Repeller and of the Cold Spot Repeller, two large influential cosmic voids, and the discovery of the South Pole Wall, a large-scale structure located in the direction of the south celestial pole beyond the southern frontiers of Laniakea.

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">ESO 383-76</span> Elliptical 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 540.89 kiloparsecs, it is one of the largest galaxies known.

The Southern Supercluster Strand is a galaxy filament that incompasses the Southern Supercluster and the Telescopium−Grus Cloud.

References

  1. 1 2 Proust, Dominique; Quintana, Hernán [in Spanish]; Carrasco, Eleazar R.; Reisenegger, Andreas; Slezak, Eric; Muriel, Hernán; Dünner, Rolando; Sodré, Laerte Jr.; Drinkwater, Michael J. [in Italian]; Parker, Quentin A.; Ragone, Cinthia J. (June 2006). "The Shapley supercluster: the largest matter concentration in the local Universe" (PDF). The Messenger. European Southern Observatory (ESO). 124 (124): 30–31. Bibcode:2006Msngr.124...30P. OCLC   992894162.
  2. ↑ "The Shapley Supercluster". www.atlasoftheuniverse.com. Retrieved 2020-09-23.
  3. ↑ Raychaudhury, Somak (November 1989). "The distribution of galaxies in the direction of the 'Great Attractor'". Nature. 342 (6247): 251–255. Bibcode:1989Natur.342..251R. doi:10.1038/342251a0. ISSN   1476-4687. S2CID   4354365.
  4. ↑ Scaramella, R.; Baiesi-Pillastrini, G.; Chincarini, G.; Vettolani, G.; Zamorani, G. (April 1989). "A marked concentration of galaxy clusters: is this the origin of large-scale motions?". Nature. 338 (6216): 562–564. Bibcode:1989Natur.338..562S. doi:10.1038/338562a0. ISSN   1476-4687. S2CID   4336689.
  5. ↑ "What is the Great Attractor?". 14 July 2014.
  6. ↑ Hoffman, Yehuda; Pomarède, Daniel; Tully, R. Brent; Courtois, Hélène M. (30 January 2017). "The dipole repeller". Nature Astronomy. 1 (2): 0036. arXiv: 1702.02483 . Bibcode:2017NatAs...1E..36H. doi:10.1038/s41550-016-0036. S2CID   7537393.
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