Abell 1656 — LLMpedia

Abell 1656
Taavi Niittee/Tõrva Astronoomiaklubi/Tõrva Astronomy Club · CC BY 4.0 · source
Name	Coma Cluster
Epoch	J2000
Constellation	Coma Berenices (constellation)
Distance	321 million ly
Redshift	0.023
Type	Galaxy cluster
Mass	~10^15 solar masses
Other names	Abell 1656

Contents

Abell 1656 is a rich, nearby galaxy cluster in Coma Berenices (constellation) notable for its high galaxy density, strong X-ray emission, and role as a laboratory for galaxy evolution and cosmology. It has been extensively observed with facilities such as the Hubble Space Telescope, Chandra X-ray Observatory, and Very Large Array, and has influenced studies by teams from the Mount Wilson Observatory, Palomar Observatory, and the Sloan Digital Sky Survey. The cluster figures in analyses by researchers associated with institutions like the Max Planck Institute for Astrophysics, Harvard–Smithsonian Center for Astrophysics, and the Institute of Astronomy, Cambridge.

Overview

The Coma Cluster occupies a significant place in extragalactic astronomy, linking work by George O. Abell, surveys from the Palomar Observatory Sky Survey, and interpretations by theorists at the Princeton University cosmology group. It served as a benchmark in comparisons with clusters such as Virgo Cluster, Fornax Cluster, and the Perseus Cluster, and has been used to calibrate distance scales alongside projects like the Hubble Key Project and the Tully–Fisher relation studies. Observational programs from the Two Micron All Sky Survey and the Galaxy and Mass Assembly survey supplemented redshift catalogs produced by teams at the University of Tokyo and the European Southern Observatory.

The cluster contains thousands of member galaxies dominated by giant ellipticals including two central cD galaxies historically cataloged in surveys at the Cerro Tololo Inter-American Observatory and the Kitt Peak National Observatory. Prominent members have been targets for spectroscopic campaigns by the Keck Observatory and the Very Large Telescope. Studies drawing on data from the Sloan Digital Sky Survey and the NASA/IPAC Extragalactic Database identified morphological segregation comparable to findings in the Dressler (1980) density–morphology relation and in surveys by the Zwicky Catalog teams. Galaxy populations have been classified in follow-up imaging from the Subaru Telescope, the Gemini Observatory, and the Canada–France–Hawaii Telescope.

X-ray observations by the Einstein Observatory, the ROSAT mission, the XMM-Newton satellite, and the Chandra X-ray Observatory revealed a hot intracluster medium with temperatures measured by groups at the Astrophysical Institute Potsdam and the University of Leicester. Spectroscopic analyses using models from the MEKAL model community and software like XSPEC determined metal abundances linked to enrichment by supernovae studied by teams at the Max Planck Institute for Extraterrestrial Physics and the European Space Agency. Cooling flow signatures and entropy profiles have been compared with simulations from the Illustris Project and the Millennium Simulation by researchers at institutions including the University of California, Berkeley and the Flatiron Institute.

Kinematic studies using redshift surveys from the Sloan Digital Sky Survey and velocity dispersion analyses conducted by astronomers at the University of Cambridge and Columbia University established a high total mass consistent with gravitational lensing results from investigations by the Hubble Space Telescope teams and the CFHTLens collaboration. Mass estimates derived by members of the Planck Collaboration via the Sunyaev–Zel'dovich effect were compared to X-ray hydrostatic masses from groups at the Harvard–Smithsonian Center for Astrophysics and numerical predictions from the ENZO Project and the GADGET code community. Dark matter distribution studies invoked methods used by analysts from the Max Planck Institute for Astrophysics and the Kavli Institute for Cosmology.

Diffuse radio halo and relic emission were mapped by arrays such as the Very Large Array, the Giant Metrewave Radio Telescope, and the Low-Frequency Array. Investigations by researchers at the Netherlands Institute for Radio Astronomy and the National Radio Astronomy Observatory tied nonthermal components to cosmic ray populations studied by teams at the Fermi Gamma-ray Space Telescope consortium and particle astrophysics groups at the CERN theory division. Polarization studies referenced work from the Australian Square Kilometre Array Pathfinder teams and models developed at the Max Planck Institute for Radio Astronomy.

Situated within the Coma Supercluster and connected to filaments identified in the Two-degree Field Galaxy Redshift Survey, the cluster's environment has been characterized with help from surveys at the European Southern Observatory and simulations from the Bolshoi Simulation. Its role in large-scale structure studies relates to analyses by the Sloan Digital Sky Survey collaboration, the 2MASS Redshift Survey teams, and cosmological interpretations pursued at the Institute for Advanced Study and the Lawrence Berkeley National Laboratory.

The cluster entered the literature through the Abell catalogue compiled by George O. Abell and was a focus of early dynamical work by Fritz Zwicky on missing mass that influenced the dark matter paradigm. Subsequent landmark studies include X-ray mapping by the Einstein Observatory teams, radio halo identification by observers using the Westerbork Synthesis Radio Telescope, and deep optical spectroscopy from projects at the Keck Observatory and the Subaru Telescope. Long-term monitoring and legacy programs involve collaborations among the National Aeronautics and Space Administration, the European Space Agency, and university groups at the University of Chicago and the University of Oxford.

Category:Galaxy clusters