Shapley Supercluster

Shapley Supercluster

The Shapley Supercluster (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, approximately 650 million light years from the Milky Way.

In recent times, the Shapley supercluster was rediscovered by Somak Raychaudhury, [ [http://www.nature.com/nature/journal/v342/n6247/abs/342251a0.html The distribution of galaxies in the direction of the 'Great Attractor' Somak Raychaudhury Nature 342, 251-255 (1989)] ] 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 a remarkable concentration of clusters in the Abell catalogue of clusters of galaxies: they had named it the "Alpha concentration". [ [http://www.nature.com/nature/journal/v338/n6216/abs/338562a0.html A marked concentration of galaxy clusters: is this the origin of large-scale motions? R. Scaramella et al. Nature 338, 562 (1989)] ]

History

In the late 1920s, 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.

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 CMB frame. This has led many to speculate that the Shapley Supercluster may indeed be one of the major causes of our peculiar motion (the Great Attractor), and has led to a surge of interest in this Supercluster.

References

External links

* [http://eaa.crcpress.com/?action=summary&doc=eaa/2137@eaa-xml&qt= Article on the Shapley Supercluster in the Encyclopedia of Astronomy and Astrophysics]
* [http://www.atlasoftheuniverse.com/superc/shapley.html An atlas of the Universe]
* [http://www.ira.cnr.it/~tventuri/shapley.html The Shapley Concentration]
* [http://www.cfa.harvard.edu/hco/ Harvard College Observatory]

ee also

* Great Attractor
* Hydra-Centaurus Supercluster
* Norma Cluster


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Harlow Shapley — (* 2. November 1885 in Nashville, Tennessee; † 20. Oktober 1972 in Boulder, Colorado) war ein US amerikanischer Astronom. 1913 promovierte Harlow Shapley an der Princeton University bei Henry Norris Russell mit der Arbeit The Orbits of Eighty… …   Deutsch Wikipedia

  • Harlow Shapley — Infobox Scientist name = PAGENAME box width = image size =150px caption = PAGENAME in his earlier years birth date = November 2 1885 birth place = Nashville, Missouri death date = October 20 1972 death place = residence = citizenship =… …   Wikipedia

  • Large-scale structure of the cosmos — In physical cosmology, the term large scale structure refers to the characterization of observable distributions of matter and light on the largest scales (typically on the order of billions of light years). Sky surveys and mappings of the… …   Wikipedia

  • Great Attractor — NOTOC The Great Attractor is a gravity anomaly in intergalactic space within the range of the Centaurus Supercluster that reveals the existence of a localised concentration of mass equivalent to tens of thousands of Milky Ways, observable by its… …   Wikipedia

  • Обсерватория Бойдена — Оригинал названия Boyden Observatory Тип астрономическая обсерватория Код 074  (наблюдения) Расположение Блумфонтейн, Фри Стейт …   Википедия

  • Шепли, Харлоу — В Википедии есть статьи о других людях с такой фамилией, см. Шепли. Харлоу Шепли Harlow Shapley Дата рождения: 2 ноября 1885 …   Википедия

  • 1 yottametre — To help compare different orders of magnitude, this page lists distances starting at 1 Ym (1024 m or 110 million light years). Distances shorter than 10 Ym 1.2 Ym 127 million light years Distance to the closest observed gamma ray burst GRB 980425 …   Wikipedia

  • Grand Attracteur — Le Grand Attracteur est une anomalie gravitationnelle prédite en 1987. L expansion de l univers devrait forcer les galaxies à s éloigner les unes par rapport aux autres. Or il semble que notre galaxie, notre groupe local, et tout ce qui nous… …   Wikipédia en Français

  • Somak Raychaudhury — Dr Somak Raychaudhury (born 1962 in Kolkata, India) is an astrophysicist. He is currently a Senior Lecturer at the University of Birmingham, England. Besides teaching various Astronomy Cosmology courses at the undergraduate level and supervising… …   Wikipedia

  • Dark flow — Physical cosmology Universe · Big Bang …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”