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. 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.
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.
The Las Campanas Redshift Survey is considered the first attempt to map a large area of the universe out to a redshift of z = 0.2. It was begun in 1991 using the Las Campanas telescope in Chile to catalog 26418 separate galaxies. It is considered one of the first surveys to document the so-called "end of greatness" where the Cosmological Principle of isotropy could be seen. Superclusters and voids are prominent features in the survey.
The Sloan Great Wall (SGW) is a cosmic structure formed by a giant wall of galaxies. Its discovery was announced from Princeton University on October 20, 2003, by J. Richard Gott III, Mario Jurić, and their colleagues, based on data from the Sloan Digital Sky Survey.
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.
The Einasto profile is a mathematical function that describes how the density of a spherical stellar system varies with distance from its center. Jaan Einasto introduced his model at a 1963 conference in Alma-Ata, Kazakhstan.
The Hercules Superclusters refers to a set of two nearby superclusters of galaxies.
Abell 222 is a galaxy cluster in the constellation of Cetus. It holds thousands of galaxies together. It is located at a distance of 2.4 billion light-years from Earth.
Abell 223 is a galaxy cluster. It is located at a distance of 2.4 billion light-years from Earth. The cluster is connected to nearby cluster Abell 222 by a filament of matter. Research has shown that only 20% of that matter is normal. The rest is thought to be dark matter. This means that this would form the Abell 222/ Abell 223 Supercluster as we understand them.
Bahcall–Wolf cusp refers to a particular distribution of stars around a massive black hole at the center of a galaxy or globular cluster. If the nucleus containing the black hole is sufficiently old, exchange of orbital energy between stars drives their distribution toward a characteristic form, such that the density of stars, ρ, varies with distance from the black hole, r, as
Cosmic voids are vast spaces between filaments, which contain very few or no galaxies. The cosmological evolution of the void regions differs drastically from the evolution of the Universe as a whole: there is a long stage when the curvature term dominates, which prevents the formation of galaxy clusters and massive galaxies. Hence, although even the emptiest regions of voids contain more than ~15% of the average matter density of the Universe, the voids look almost empty for an observer. Voids typically have a diameter of 10 to 100 megaparsecs ; particularly large voids, defined by the absence of rich superclusters, are sometimes called supervoids. They were first discovered in 1978 in a pioneering study by Stephen Gregory and Laird A. Thompson at the Kitt Peak National Observatory.
The Laniakea Supercluster is the galaxy supercluster that is home to the Milky Way and approximately 100,000 other nearby galaxies. It was defined in September 2014, when a group of astronomers including R. Brent Tully of the University of Hawaiʻi, Hélène Courtois of the University of Lyon, Yehuda Hoffman of the Hebrew University of Jerusalem, and Daniel Pomarède of CEA Université Paris-Saclay published a new way of defining superclusters according to the relative velocities of galaxies. The new definition of the local supercluster subsumes the prior defined local supercluster, the Virgo Supercluster, as an appendage.
The BOSS Great Wall is a supercluster complex that was identified, using the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS), in early 2016. It was discovered by a research team from several institutions, consisting of: Hiedi Lietzen, Elmo Tempel, Lauri Juhan Liivamägi, Antonio Montero-Dorta, Maret Einasto, Alina Streblyanska, Claudia Maraston, Jose Alberto Rubiño-Martín and Enn Saar. The BOSS Great Wall is one of the largest superstructures in the observable universe, though there are even larger structures known.
The Caelum Supercluster, also known as SCl 59, may be a massive supercluster; spanning 910 million light-years, it is perhaps the largest galaxy supercluster in the universe. It has a mass of 2×1017 solar masses, 1.7 times the mass of Laniakea Supercluster and of Horologium Supercluster. It is centered on coordinates right ascension 04h 43m and declination −33° 30′.
NGC 973 is a giant spiral galaxy located in the constellation Triangulum. It is located at a distance of circa 200 million light-years from Earth, which, given its apparent dimensions, means that NGC 973 is about 230,000 light years across. It was discovered by Lewis Swift on October 30, 1885.
The NGC 4065 Group is a group of galaxies located about 330 Mly (100 Mpc) in the constellation Coma Berenices. The group's brightest member is NGC 4065 and located in the Coma Supercluster.
NGC 7836 is an irregular or spiral galaxy located about 260 million light-years away in the constellation of Andromeda. It was discovered by astronomer Lewis Swift on September 20, 1885.
NGC 3925 is a barred lenticular galaxy and a ring galaxy located about 370 million light-years away in the constellation Leo. It was discovered by astronomer Heinrich d'Arrest on February 19, 1863.
