Astrophysics (Index)About

galaxy cluster

(CL, cluster)
(large group of galaxies gravitationally-bound to the group)

A galaxy cluster (CL) is a group of on the order of hundreds of galaxies bound to each other by gravity. A smaller such group of galaxies is known as a galaxy group. The vast majority of galaxies are in such clusters and groups. The cluster often has an intergalactic medium including plasma. The typical mass of a cluster is on the order of 1015 solar masses. A cluster can be part of a supercluster. Shock waves from matter striking a galaxy cluster's intracluster medium produce X-rays, which can be a sign to observers of the presence of a galaxy cluster. Such X-ray signals can reveal very distant clusters, the furthest currently known (CL J1001+0220) being at redshift 2.5. Example galaxy clusters:

The abbreviation CL is often included in designators for galaxy clusters, e.g., for CL J1001+0220.

The term cluster can also refer to stellar clusters such as open clusters, sometimes confusingly called galactic clusters (meaning clusters within a galaxy, i.e., the Milky Way).

(galaxies,object type)
Further reading:
CLCL J1001+0220or CLG, general prefix for clusters

Referenced by pages:
Abell Catalog
Atacama Cosmology Telescope (ACT)
Arecibo General Catalog (AGC)
Alcock-Paczyński effect (AP effect)
Arcminute Microkelvin Imager (AMI)
astronomical quantities
baryonic matter
Bautz-Morgan classification
brightest cluster galaxy (BCG)
Bullet Cluster
Canadian Cluster Comparison Project (CCCP)
cold dark matter (CDM)
Catalog of Galaxies and Clusters of Galaxies (CGCG)
cosmic infrared background (CIB)
cluster radius
CMB lensing
Comet Galaxy
comoving units
Compton scattering
computational astrophysics
cooling flow
cosmic distance ladder
cosmic web
cosmological simulation
dark flow
dark matter
dark matter halo
Dark Energy Survey (DES)
diffuse emission
velocity dispersion (σ)
dark matter filament
Duus-Newell catalog (DN)
elliptical galaxy
ESO Nearby Abell Cluster Survey (ENACS)
ESO 137-001
extended source
extragalactic astronomy
field galaxy
galaxy bias
galaxy cloud
galaxy environment
galaxy filament
galaxy group
galaxy harassment
galaxy subgroup
gas fraction
gravitational instability (GI)
giant elliptical galaxy
gravitational instability model
gravitational lensing
gravitationally bound
gravitational redshift
Great Wall
hierarchical assembly of galaxies
Hubble expansion
Hydra-Centaurus Supercluster
intracluster medium (ICM)
intergalactic medium (IGM)
intensity mapping
intergalactic dust
IRAC Shallow Survey (ISS)
Lambda-CDM model (ΛCDM)
Laniakea Supercluster
large scale structure (LSS)
luminosity function (LF)
Massive Cluster Survey (MACS)
metallicity (Z)
mock catalog
Morgan classification
Munich Near-Infrared Cluster Survey (MUNICS)
non-Gaussian (NG)
Perseus-Pisces Supercluster
planetary nebula luminosity function (PNLF)
projected separation
quantum fluctuations
radio relics
rare designator prefixes
redshift survey
RR Lyrae variable (RRL)
Scott effect
star formation history (SFH)
South Pole Telescope (SPT)
standard candle
stellar dynamics
supergalactic coordinate system
Sachs-Wolfe effect (SWE)
systemic velocity
Sunyaev-Zel'dovich effect (SZ effect)
thermal bremsstrahlung
3C 295
three dimensional model
21-cm experiment
21-cm line
ultraviolet astronomy
Virgo Cluster
Virgo Supercluster
virial theorem
wide binaries (WB)
weak lensing (WL)
XMM Cluster Survey (XCS)
X-ray luminous galaxy cluster
X-ray source
Zwicky 3146 (Zw 3146)