Coma Cluster — LLMpedia

Coma Cluster
Taavi Niittee/Tõrva Astronoomiaklubi/Tõrva Astronomy Club · CC BY 4.0 · source
Name	Coma Cluster
Other names	Abell 1656
Constellation	Coma Berenices
Redshift	0.0231
Distance	321 million light-years
Richness	Richness class 2
Brightest member	NGC 4874 / NGC 4889

Contents

Coma Cluster The Coma Cluster is a nearby rich galaxy cluster in Coma Berenices known for its dense population of elliptical and lenticular galaxies and its role in studies by astronomers associated with George Abell, Fritz Zwicky, Edwin Hubble, Vera Rubin and observatories such as Palomar Observatory and Mount Wilson Observatory. It is cataloged as Abell 1656 and has been central to investigations involving instruments like the Very Large Array, Chandra X-ray Observatory, Hubble Space Telescope and the Sloan Digital Sky Survey. The cluster serves as a reference object in surveys carried out by teams from Harvard-Smithsonian Center for Astrophysics, Max Planck Institute for Astronomy, European Southern Observatory and the National Radio Astronomy Observatory.

Overview

The Coma Cluster resides in Coma Berenices and is one of the most studied nearby clusters alongside Virgo Cluster, Perseus Cluster, Fornax Cluster and Hydra Cluster, appearing in catalogs compiled by George Abell and characterized by early analyses from Fritz Zwicky and later redshift surveys by Margaret Geller and John Huchra. Its projected extent and high galaxy density made it a target for mapping projects like the Two-degree Field Galaxy Redshift Survey and the Sloan Digital Sky Survey while hosting prominent galaxies such as NGC 4874 and NGC 4889 that were observed with facilities including Keck Observatory, Gemini Observatory, Subaru Telescope and Very Large Telescope.

The cluster's mass distribution was measured using techniques developed in studies by Fritz Zwicky and refined by teams at Caltech, MIT and Princeton University employing optical spectroscopy from Palomar Observatory and X-ray imaging from Chandra X-ray Observatory and XMM-Newton. The Coma region shows a roughly spherical core dominated by giant ellipticals linked to subclusters identified in mapping by Gustav Tammann and later kinematic analyses by J. A. Tyson and Sandra Faber. Mass estimates derive from virial theorem applications popularized by Edwin Hubble and gravitational lensing methods used by researchers at University of California, Berkeley and Institute for Advanced Study.

Member galaxies include the giant ellipticals NGC 4874 and NGC 4889, along with numerous dwarf ellipticals cataloged in surveys by George Abell and morphological studies by Allan Sandage and John Kormendy. The population mix contrasts with that of Virgo Cluster and displays morphology–density relation evidence discussed by Alan Dressler and Debra Elmegreen. Spectroscopic follow-up by teams led by Christopher Conselice and P. A. Goudfrooij uncovered stellar population gradients used in comparative work with M87 in Virgo Cluster and NGC 1399 in Fornax Cluster.

X-ray observations from Einstein Observatory, ROSAT, Chandra X-ray Observatory and XMM-Newton revealed a hot intracluster medium rich in ionized plasma and heavy elements studied by researchers at Harvard-Smithsonian Center for Astrophysics and Max Planck Institute for Astrophysics. Measurements of the Sunyaev–Zel'dovich effect by teams using the Atacama Cosmology Telescope and Planck (spacecraft) complemented gravitational lensing maps from Hubble Space Telescope programs to infer dark matter distributions, a concept central to work by Fritz Zwicky, Vera Rubin and Milan Ćirković in mass discrepancy debates. High-resolution spectra from Chandra X-ray Observatory and radio imaging from the Very Large Array uncovered turbulent gas, shock fronts, and radio halos studied by groups at University of Cambridge and Max Planck Institute for Radio Astronomy.

Kinematic studies by Margaret Geller and John Huchra used redshift catalogs from Sloan Digital Sky Survey and Two-degree Field Galaxy Redshift Survey to map velocity dispersion and substructure, revealing evidence for ongoing mergers analogous to those modeled in simulations from Millennium Simulation teams and numerical work by Vera C. Rubin Observatory planners. The cluster's dynamical state informed hierarchical structure formation scenarios developed in frameworks by James Peebles, Simon White, Carlos Frenk, Richard Bower and George Efstathiou. Observational signatures of past interactions have been compared to results from hydrodynamical simulations by researchers at Princeton University and Lawrence Livermore National Laboratory.

Historical notes trace photographic plate studies at Palomar Observatory and photographic atlases by William Herschel's tradition through systematic redshift efforts by George Abell,Fritz Zwicky and later large surveys like Sloan Digital Sky Survey and Two Micron All Sky Survey. Key X-ray work by teams at Harvard-Smithsonian Center for Astrophysics and NASA's Chandra X-ray Observatory refined temperature and metallicity maps, while radio studies involving the Very Large Array and LOFAR revealed diffuse synchrotron emission that engaged researchers from University of Leiden and ASTRON.

The cluster has been pivotal in discussions about dark matter following analyses by Fritz Zwicky and rotation curve studies by Vera Rubin, and it serves as a benchmark for mass-to-light ratio measurements used in cosmological parameter estimation by groups at Planck (spacecraft), WMAP, Institute of Cosmology and Gravitation and Centre National de la Recherche Scientifique. Studies of its baryon fraction, intracluster medium enrichment and merger history contribute to constraints on models developed by Alan Guth, Andrei Linde, Paul Steinhardt and Neta Bahcall and inform comparisons with simulations from the Illustris project and Millennium Simulation.

Category:Galaxy clusters