Shapley Supercluster

Shapley Supercluster
Name	Shapley Supercluster

Shapley Supercluster is a massive concentration of galaxy clusters in the local universe whose gravitational dominance influences peculiar velocities across the nearby cosmological volume. It lies in the direction of the constellations Centaurus and Hydra near the region of the Great Attractor, and it is associated observationally with rich clusters such as Abell 3558, Abell 3562, and Abell 3571. Studies of the system have been conducted using facilities including the ROSAT, Chandra, and XMM-Newton satellites as well as ground observatories like the Anglo-Australian Telescope, European Southern Observatory, and the Very Large Telescope.

Overview

The concentration forms one of the most massive superclusters in the nearby universe mapped in redshift surveys by teams using the 2dFGRS, the 6dF, and the Sloan Digital Sky Survey; it influences motions measured in studies by the Cosmic Microwave Background groups behind the WMAP and Planck missions. Observational campaigns combining data from the Arecibo Observatory, Parkes Observatory, and radio arrays such as the Australia Telescope Compact Array have enriched knowledge of neutral hydrogen and active galactic nuclei in the region, while infrared work with the IRAS and Spitzer probes dusty star formation. The supercluster sits amid filaments and voids revealed in maps by the CfA Survey and the 2MASS Redshift Survey, contextualizing it within the Cosmic web traced by surveys like DEEP2 and the COSMOS field.

Discovery and Naming

The overdensity was first highlighted in optical cluster catalogues compiled by George O. Abell and later emphasized in work by Harlow Shapley, from whose name the system derives; early identification also involved researchers from the Australian National University and the Royal Observatory, Edinburgh. Historical plate-based studies using instruments at the Mount Wilson Observatory and the Harvard College Observatory preceded redshift confirmations from spectroscopic programs run at the Cerro Tololo Inter-American Observatory and the Kitt Peak National Observatory. Subsequent nomenclature appears in cluster catalogues such as the Abell catalog and in reviews by teams associated with the Max Planck Institute for Astrophysics and the Harvard–Smithsonian Center for Astrophysics.

Structure and Components

The assembly comprises dozens of rich clusters and groups, including prominent members catalogued as Abell 3558, Abell 3560, Abell 3562, Abell 3571, and Abell 3581, embedded in filamentary connections to superclusters like the Laniakea Supercluster and the Horologium–Reticulum Supercluster. Galaxy systems within it span morphological classes similar to those studied by Edwin Hubble and catalogued by teams at the Leiden Observatory and Cerro Tololo, with brightest cluster galaxies comparable in luminosity to central galaxies in Virgo Cluster and Coma Cluster. Inter-cluster plasma and intracluster medium structures have been mapped with the Chandra X-ray Observatory and the XMM-Newton mission, while gravitational lensing and dynamics analyses have engaged groups from the Space Telescope Science Institute and the European Southern Observatory.

Mass, Dynamics, and Gravitational Influence

Mass estimates derived from velocity dispersions measured by the Anglo-Australian Telescope and the ESO Very Large Telescope as well as from X-ray temperatures observed by ROSAT and Chandra place the total mass among the highest in the local volume, comparable in influence to the Great Attractor region and considered in flow-field analyses by the Cosmicflows project and teams led by G. A. Tully. Peculiar velocity studies connecting the overdensity to bulk flows detected by WMAP and Planck have been discussed alongside analyses from the 2MASS Redshift Survey and the Sloan Digital Sky Survey. N-body simulations performed with codes developed at institutions like the Max Planck Institute for Astrophysics and the Princeton University gravitational dynamics groups replicate the convergence of matter onto nodes represented by this supercluster.

Galaxy Populations and Star Formation

Member galaxies show a mix of quenched ellipticals concentrated in cores similar to the populations characterized in the Coma Cluster and the Fornax Cluster, alongside star-forming spirals and active nuclei analogous to systems catalogued by Sloan Digital Sky Survey teams and observed in infrared by Spitzer. Studies using spectroscopy from the Anglo-Australian Telescope and the European Southern Observatory have measured stellar populations, metallicities, and emission-line diagnostics following methods popularized by researchers at the Max Planck Institute for Astronomy and the Harvard–Smithsonian Center for Astrophysics. Radio continuum surveys with the Australia Telescope Compact Array and the Very Large Array have detected radio galaxies and jets reminiscent of sources observed in the 3C catalogue and in samples targeted by the NRAO.

X-ray and Multiwavelength Observations

X-ray imaging and spectroscopy from ROSAT, Chandra, and XMM-Newton reveal hot intracluster gas, shocks, and substructure comparable to features studied in Bullet Cluster analyses and in observations by the Suzaku mission. Ultraviolet work with GALEX and infrared datasets from Spitzer and WISE probe recent star formation and dust-obscured activity, while millimetre-wave observations by facilities like the Atacama Pathfinder Experiment and the ALMA have constrained the Sunyaev–Zel'dovich effect contributions analogous to measurements performed by the South Pole Telescope and the Atacama Cosmology Telescope. Optical imaging and redshift surveys from the Sloan Digital Sky Survey and the Dark Energy Survey provide the large-scale maps that place X-ray structures into the filamentary context defined by the 2dF Galaxy Redshift Survey.

Role in Large-Scale Structure and Cosmology

The system serves as a keystone in studies of the local velocity field and large-scale structure, informing models promoted by the Lambda-CDM framework and by simulation projects such as the Millennium Simulation and the Illustris project. Its mass concentration factors into discussions about bulk flows investigated by teams using data from WMAP and Planck and influences galaxy evolution scenarios developed at institutions like the Max Planck Institute for Astrophysics and the Institute for Advanced Study. Comparisons with other superclusters, including the Laniakea Supercluster and the Sloan Great Wall, make it a focal point for cosmological tests using surveys such as 2MASS, SDSS, and DES.

Category:Superclusters