The Hydra–Centaurus Supercluster (SCl 128),[3] or the Hydra and Centaurus Superclusters,[1] 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,[3] with it extending to a maximum distance of around 69 Mpc (225 Mly).[2]
The Antlia Wall,[4] also known as the Antlia Strand,[6][7][5]Hydra Wall,[8]Hydra-Antlia wall, Hydra-Antlia extension,[9] and the Hydra-Antlia filament,[10] is a filament that emeges from the Centaurus Cluster, passes under the Zone of Avoidance (ZOA) as the "Puppis filament",[6] to link up the Lepus Cloud.[4] This filament then passes though a region containing the NGC 1600 Group before crossing the boundary where the gravitional flows of galaxies between the Laniakea and Perseus–Pisces superclusters diverge[6] to link up with the Perseus–Pisces supercluster at a distance of around 420 Mly (130 Mpc) from the Centaurus Cluster.[7] The filament contains two major clusters:
In 2014, it was revealed that the Antlia Wall along with the rest of the Hydra–Centaurus supercluster is connected to the Perseus–Pisces Supercluster.[11] Later in 2017, Pomarède et.al identified based on the flow of galaxies that the Antlia Wall along with the Lepus Cloud are part of a substantial filament known as the Centaurus–Puppis–PP Filament[6] that extends around 420 Mly (130 Mpc) from the Centaurus Cluster all the way to the Perseus–Pisces supercluster.[7] The Centaurus–Puppis–PP Filament along with the Southern Supercluster Strand[6] which contains the Eridanus-Fornax-Dorado Filament and the Telescopium−Grus Cloud,[4] are part of wall that makes up the front boundary of the Sculptor Void.
Before 2017, it was not known that the Antlia Wall and the Lepus Cloud were part of the same structure, the Centaurus–Puppis–PP Filament. This is because the Centaurus–Puppis–PP Filament goes under the ZOA of the Milky Way, which caused parts of the filament to be obscured by the disk of the galaxy on the sky, resulting in the naming of the different visible pieces of filament.[6]
Apart from the central clusters, which are 150 to 200 million light years away, several smaller clusters belong to the group.
Within the proximity of this supercluster lies the Great Attractor, dominated by the Norma Cluster (Abell 3627). This massive cluster of galaxies exerts a large gravitational force, causing all matter within 50 Mpc to experience a bulk flow of 600 km/s toward the Norma Cluster.[12]
A 2014 announcement says that the Centaurus Supercluster (Hydra–Centaurus) is just a lobe in a greater supercluster, Laniakea, that is centered on the Great Attractor. That supercluster would include the Virgo Supercluster, therefore including the Milky Way where Earth resides.
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