Pisces–Cetus Supercluster Complex


The Pisces–Cetus Supercluster Complex or the local superstructure is a galaxy supercluster complex that includes the Virgo Supercluster as its outlying member, which in turn contains the Local Group, the galaxy group that includes the Milky Way. The complex was named after the Pisces–Cetus Superclusters, which are its richest and most prominent superclusters and reside in as its core and of its main plane, located at roughly away from Earth. A supercluster complex is defined as container of several dozens of rich clusters and large superclusters.

Observational history

Astronomer R. Brent Tully of the University of Hawaii's Institute of Astronomy discovered a very massive agglomeration that includes the Local and Pisces–Cetus Superclusters in 1986, and identified it as the "extended Pisces–Cetus Supercluster", and later the Pisces–Cetus Supercluster Complex in 1987. In addition, four more other nearby supercluster complexes within a redshift of z = 0.1 have also been discovered, including Ursa Major, Hercules-Corona Borealis, Leo, and Aquarius Supercluster Complexes. The Aquarius Supercluster Complex was known to contain 25 rich galaxy clusters and is composed of two parts, which are both the Aquarius Region and the Aquarius-Capricornus Region. It along with Pisces–Cetus Supercluster Complex have been shown to contains most of the 114 southern Abell clusters. Only 28 are not associated with these two main complexes, with no other association having more than four members.
Following the discovery of those supercluster complexes at the end of the 20th century, more other supercluster complexes were later identified such as Sloan Great Wall and BOSS Great Wall.

Extent

The Pisces–Cetus Supercluster Complex is estimated to be about long and wide, making it one of the largest structures known in the observable universe. This brings it to roughly the theoretical limit per the Cosmological Principle. Despite that, larger sizes have been suggested for other structures such as Quipu superstructure, Clowes–Campusano LQG and U1.11, along with the disputed and unconfirmed Huge-LQG, Giant GRB Ring, and Hercules–Corona Borealis Great Wall.
61 rich clusters comprise the complex, which is estimated to have a total mass of approximately times that of the mass of the Sun. According to the discoverer, the complex is composed of 5 parts:
  1. The
  2. The Perseus–Pegasus chain, including the Perseus–Pisces Supercluster
  3. The Pegasus–Pisces chain
  4. The Sculptor region, including the Sculptor Superclusters
  5. The Laniakea, which contains our Virgo Supercluster as well as the Hydra–Centaurus Supercluster.
With its mass of, our Virgo Supercluster accounts for only 0.1 percent of the total mass of the complex. Coma Supercluster was also considered to be part of this complex by the time of its discovery in 1986, which forms the heart of Coma Filament and the larger CfA2 Great Wall.
Latest observations of basins of attraction suggested a basin of attraction around Ophiuchus Cluster may be associated with Laniakea, and also have found both, along with Apus and Coma Superclusters, are moving toward the greater Shapley Attractor and may be thus part of the Shapley Concentration.