List of galaxy clusters

This page lists some of the more interesting galaxy clusters and groups.

Defining the limits of galaxy clusters is imprecise as many clusters are still forming. In particular, clusters close to the Milky Way tend to be classified as galaxy clusters even when they are much smaller than more distant clusters.

Contents

List of groups and clusters

Galaxy cluster Notes
Bullet Cluster This collision between two galaxy clusters seems to have left a dark matter cluster in the space between them.[1]
Abell 520 This is actually a collision between two galaxy clusters. The galaxies and the dark matter seems to have separated out into separate dark and light cores.[2]
Abell 2142 A collision between two massive, X-ray luminous galaxy clusters.
Cl 0024+17
( ClG 0024+16 , ZwCl 0024+1652 )		 This is a recently coalesced merger of galaxy clusters, which has resulted in a ring of dark matter around the galaxies, yet to be redistributed.[3][4]

List of named clusters

This is a list of galaxy clusters and groups that are well known by something other than an entry in a catalog or list, or a set of coordinates, or a systematic designation.

Galaxy cluster Origin of name Notes
Local Group This is the galaxy group that we belong to.
Bullet Cluster This is actually two galaxy clusters in collision.
Burbidge Chain
Copeland Septet
Deer Lick Group Coined by Tomm Lorenzin (author of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing") to honor Deer Lick Gap in the mountains of North Carolina, from which he had especially fine views of the galaxy group. It is also called the NGC 7331 Group, after the brightest member of the group.[5]
Leo Triplet This is named for the fact it contains only three galaxies. This small group of galaxies lies in the constellation Leo.
Markarian's Chain This stretch of galaxies forms part of the Virgo Supercluster.
Robert's Quartet It was named by Halton Arp and Barry F. Madore, who compiled A Catalogue of Southern Peculiar Galaxies and Associations in 1987. This is compact group of galaxies lies 160 million light-years away in the Phoenix constellation.
Seyfert's Sextet This is named after its discoverer, Carl Seyfert, and at the time it appeared to contain six external nebulae. It is also called the NGC 6027 Sextet, after its brightest element. There are actually only five galaxies in the sextet, and only four galaxies in the compact group, one of the "galaxies" is actually part of another of the galaxies. The group is therefore more properly called HCG 79, because the name refers to a visual collection and not a cluster. HCG 79 lies 190 million light-years away in the Serpens Caput constellation.
Stephan's Quintet (Stephan's Quartet) This is named after its discoverer, Édouard Stephan. There are actually only four galaxies in the compact group, the other galaxy is a foreground galaxy. The group is therefore more properly called HCG 92, because the name refers to a visual collection and not a cluster. Thus, the real group is also called Stephan's Quartet
Wild's Triplet
Zwicky's Triplet

Major nearby groups and clusters are generally named after the constellation they lie in. Many groups and clusters are named after the leading galaxy in the group or cluster. This represents an ad hoc systematic naming system.

List of naked-eye groups

There is only one galaxy group or cluster visible to the naked eye, that would be our group of galaxies, the Local Group, if the requirement of visually sighting a cluster requires two or more galaxies. If the requirement also requires that the galaxies been somewhat close together in the sky, then no group or cluster is visually identifiable. However, the Magellanic Clouds, as a pair of galaxies, is visually discernible. The Maffei Group, the nearest galaxy group, would be visible by the naked eye if it were not obscured by the stars and dust clouds of the galactic nucleus.

Galaxy cluster Number of visible galaxies Notes
Local Group 5 If we exclude the Milky Way Galaxy, only 4 galaxies are visible to the naked-eye.[6]
M81 Group 1 Only Bode's Galaxy (M81, NGC 3031) is visible to the naked-eye.[6][7]
Centaurus A/M83 Group 2 Both Centaurus A and M83 have been seen with the naked eye [8][9]
Sculptor Group (South Polar Group) 1 Only the Sculptor Galaxy (NGC 253) can be seen with the naked eye.[10]

Firsts

First Galaxy cluster Date Notes
First galaxy cluster discovered Virgo Cluster 1784 It was discovered by Charles Messier [11]
First galaxy group discovered
First compact galaxy group discovered Stephan's Quartet (Stephan's Quintet) 1877 It was discovered by Edouard Stephan.
First proto-cluster discovered
First double galaxy discovered Magellanic Clouds antiquity

Extremes

Title Galaxy cluster Data Notes
Most distant galaxy cluster ClG J1449+0856 z=2.07 [12][13][14]
Nearest galaxy cluster Virgo Cluster This cluster is the core cluster of the galaxy supercluster our galaxy group belongs to.
Most distant galaxy group
Nearest galaxy group Local Group 0 distance This is the galaxy group that our galaxy belongs to.
Nearest neighbouring galaxy group
Most distant massive proto-cluster COSMOS-AzTEC3 z=5.3
12.6 billion light years		 [15][16]
Least massive galaxy group
Most massive galaxy cluster RX J1347.5-1145
  • mass= 2.0 ± 0.4 × 1015 MSun
  • distance: z= 0.451
  • LX-ray = 6.0 ± 0.1 × 1045 erg/s in the [2-10] keV energy band
  • temperature: kT = 10.0 ± 0.3 keV
 [17][18]
Most massive distant galaxy cluster 2XMM J083026+524133
  • mass= 5.6 × 1014 MSun
  • distance: z= 0.99 ± 0.03
  • Lbolometric= 1.8 × 1045 erg/s
  • temperature= 8.2 ± 0.9 keV ( ~95 MK for the intra-cluster gas )
 The hottest, most X-ray luminous cluster at redshifts z ≥ 1 (z= 0.99 ± 0.03).[19] [17]

Closest groups and clusters

Galaxy Groups closer than the Virgo Cluster
Galaxy cluster Distance Spectral shift Notes
Local Group 0 0 This is the galaxy group that our galaxy belongs to.
LGG 104 (IC 342/Maffei Group , IC 342 / Maffei 1 Group , IC 342 Maffei 1-2 Group) z=0.000868 The IC 342/Maffei Group contains two subgroups, the IC 342 subgroup (IC 342 Group) and the Maffei 1 subgroup (Maffei subgroup , Maffei 1 Group , Maffei Group).
M81 Group (NGC 3031 Group) 11 Mly (3.5Mpsc) z=0.001115 [20]
Centaurus A/M83 Group (Centarus A Group , M83 Group) 12 Mly (3.66Mpsc) z=0.000999 The Centaurus A/M83 Group contains two subgroups, the Centaurus A subgroup (Centaurus A Group , NGC 5128 Group , LGG 344) and the M83 subgroup (M83 Group , NGC 5236 Group , LGG 355).
Sculptor Group (South Polar Group) 12.75 Mly (3.9Mpsc)
Canes Venatici Group (Canes Venatici I Group , Canes I Group , M94 Group , NGC 4736 Group , LGG 291) 13 Mly (4Mpsc) z=0.001612
NGC 1023 Group (LGG 70) 20 Mly (6.12Mpsc) z=0.002926
M101 Group (NGC 5457 Group , LGG 371) 24 Mly (7.33Mpsc) z=0.001288
NGC 2997 Group (LGG 180) 25 Mly (7.66Mpsc) z=0.002615
Canes Venatici II Group (Canes II Group) 26 Mly (8Mpsc)
M51 Group (NGC 5194 Group , LGG 347) 31 Mly (9.5Mpsc) z=0.001850 [20]
Leo Triplet (M66 Group , NGC 3627 Group , LGG 231) 35 Mly (10.75Mpsc) z=0.002207
Leo Group (Leo I Group , M96 Group , NGC 3379 Group , LGG 217) 38 Mly (11.66Mpsc) z=0.002267
Draco Group 40 Mly (12.25Mpsc)
LGG 396 (NGC 5866 Group , NGC 5907 Group) z=0.003020
Ursa Major Group (Ursa Major I Group , M109 Group , NGC 3992 Group , NGC 3726 Group , LGG 258) 55 Mly (16.88Mpsc) z=0.003388 [20]
  • Mly represents millions of light-years, a measure of distance.
  • Distances are measured from Earth, with Earth being at zero.
10 Closest Clusters
Galaxy cluster Distance Notes
Virgo Cluster (Virgo I Cluster) z=0.0038
59 Mly (18Mpsc)		 This is the core cluster of the supercluster our galaxy group belongs to.[21]
Fornax Cluster (Abell S 373 , AM 0336-353 , MCL 52) z=0.0046
 [21]
Antlia Cluster (Abell S 636) z=0.0087
32.66 Mly (10Mpsc)		 Also called the Antlia Group.
Centaurus Cluster (Abell 3526 , Cl 1247-4102) z=0.0110
 [21]
Hydra Cluster (Hydra I Cluster , Abell 1060 , Cl 1034-2716) z=0.0114
 [21]
  • Mly represents millions of light-years, a measure of distance.
  • z represents redshift, a measure of recessional velocity and inferred distance due to cosmological expansion
  • Distances are measured from Earth, with Earth being at zero.
Closest Neighbouring Cluster or Group Recordholder
Galaxy cluster Date Distance Notes
Local Group always (closest group or cluster)

1936 − eternity

 0 for reference Components of the Local Group have always been visible in the night sky. However, the Local Group as a group was identified in 1936. This is the closest cluster to us, as our galaxy is a member of it.[11]
M81 Group (NGC 3031 Group) 11 Mly (3.5Mpsc) [20][22]
M83 Group (NGC 5236 Group , LGG 355) The BCG of this subgroup had its redshift determined early on.
Virgo Cluster
  • 1784 - (group or cluster)
  • 1784 - eternity (cluster)
 59 Mly (18Mpsc) This was the first noted cluster of "nebulae" that would become galaxies. Galaxies were not identified as such until the 1920s. This is still the nearest cluster of galaxies to us.[11]
  • Mly represents millions of light-years, a measure of distance.
  • Distances are measured from Earth, with Earth being at zero.

Farthest clusters

5 Furthest Clusters
Galaxy cluster Distance Notes
  • z represents redshift, a measure of recessional velocity and inferred distance due to cosmological expansion
Remotest Cluster Titleholder
Galaxy cluster Date Distance Notes
CL J1449+0856
(ClG J1449+0856)		 2011- z=2.07 [12][13][14]
JKCS 041 2009–2011 z=1.9
XMMXCS 2215-1738 (XMMXCS 2215.9-1738) 2006–2009 z=1.45 XMM-XCS 2215-1738 was also the most massive early cluster so far discovered.[23][24]
ISCS J143809+341419 2005–2006 z=1.41 [25][26]
XMMU J2235.3-2557 2005 z=1.393 [27][28][29][30]
RDCS 0848+4453 ( RDCS0848.6+4453 , RX J0848+4453 , ClG 0848+4453 ) 1997 - z=1.276 ClG 0848+4453 forms a double-cluster supercluster with RDCS J0849+4452 [31][32][33][34][35]
galaxy cluster around 3C 324 (3C 234 Cluster) 1984 - z=1.206 At the time, the BCG, 3C324 was the most distant non-quasar galaxy.[36]
Cl 1409+524 1960 − 1975 z=0.461 The measurement of 3C295's redshift in 1960 also defined its cluster's position. 3C 295 was also the most distant galaxy of the time.[37][38]
Abell 732 (fainter Hydra Cluster Cl 0855+0321) 1951 − 1960 z=0.2 (V=61000 km/s) Attempts at measuring the redshift of the brightest cluster galaxy of this Hydra Cluster had been attempted for years before it had been successfully achieved. The BCG was also the most distant galaxy of the time.[37][39][40][41]
Abell 1930 (Bootes Cluster) 1936 − 1951 z=0.13 (V=39000 km/s) The BCG of this cluster was also the most distant galaxy of the time.[40][42]
Gemini Cluster (Abell 568) 1932 − 1936 z=0.075
(V=23000 km/s)		 The BCG of this cluster was the most distant galaxy at the time.[42][43]
WH Christie's Leo Cluster 1931 − 1932 z=
(V=19700 km/s)		 The BCG of this cluster was the most distant galaxy known at the time.[40][43][44][45][46]
Baede's Ursa Major Cluster 1930 − 1931 z=
(V=11700 km/s)		 The BCG of this cluster was the highest redshift galaxy of the time.[46][47]
Coma Cluster 1929 − 1930 z=0.026
(V=7800 km/s)		 This cluster's distance was determined by one of the NGC objects lying in it, NGC4860.[47][48]
Pegasus Group (LGG 473 , NGC 7619 Group) 1929 z=0.012
(V=3779 km/s)		 The BCG for this group was used to measure its redshift. Shortly after this was publicized, it was accepted that redshifts were an acceptable measure of inferred distance.[49]
Cetus Group (Holmberg 45 , LGG 27) 1921 − 1929 z=0.006
(V=1800 km/s)		 NGC 584 (Dreyer 584) was measured for the redshift to this galaxy group.[49][50][51][52]
Virgo Cluster 1784 − 1921 59 Mly (18Mpsc)
z=0.003 (V=1200 km/s)		 This was the first noted cluster of "nebulae" that would become galaxies. The first redshifts to galaxies in the cluster were measured in the 1910s. Galaxies were not identified as such until the 1920s. The distance to the Virgo Cluster would have to wait until the 1930s.[11]
  • z represents redshift, a measure of recessional velocity and inferred distance due to cosmological expansion
5 Farthest Protoclusters
Galaxy cluster Distance Notes
  • z represents redshift, a measure of recessional velocity and inferred distance due to cosmological expansion
Most Remote Proto-Cluster Titleholder
Galaxy protocluster Date Distance Notes
COSMOS-AzTEC3 2011 - z=5.3 Located in Sextans, the cluster appears to contain 11 young small galaxies.[16][61]
proto-cluster around radio-galaxy TN J1338-1942 2002 - z=4.11 It was described as the most distant cluster.[62][63][64][65]
proto-cluster around 3C 368 1982 - z=1.13 [66]
  • z represents redshift, a measure of recessional velocity and inferred distance due to cosmological expansion

False clusters

Through researching of galaxy association, sometimes clusters are put forward that are not genuine clusters or superclusters, but rather random collections of groups that chance alignment makes it seem is a cluster.

Galaxy cluster Notes
Cancer Cluster The Cancer Cluster was found to be a random assortment of galaxy groups, and not a true cluster.[11]
Coma-Virgo Cloud The early identification of the Coma-Virgo Cloud of Nebulae was actually a mistaken identification due to the superposition of the Virgo Supercluster and Coma Supercluster, and not a Coma-Virgo Supercluster

Lists of groups and clusters

Citations

  1. ^ Universe Today, Galaxy Collision Separates Out the Dark Matter 2006-08-21
  2. ^ Universe Today, Galaxy Cluster Collision Creates a Dark Matter Core 2007-08-16
  3. ^ Universe Today, Ring of Dark Matter Discovered Around a Galaxy Cluster 2007-05-15
  4. ^ SIMBAD, "ClG 0024+17"
  5. ^ Saratoga Skies, "NGC 7331 (Deer Lick Group and Stephan's Quintet)", Jim Solomon (accessed 7 May 2009)
  6. ^ a b Stephen Uitti (27-May-2005). "Farthest Naked Eye Object". Uitti.net. http://www.uitti.net/stephen/astro/essays/farthest_naked_eye_object.shtml. Retrieved 2008-11-01. 
  7. ^ SEDS, Messier 81
  8. ^ http://astronomy-mall.com/Adventures.In.Deep.Space/aintno.htm
  9. ^ http://www.springerlink.com/content/q1696565458u3286/
  10. ^ Brian A. Skiff claims here that the naked eye visibility of this galaxy is discussed in an old Sky & Telescope letter or note from the late 1960s or early 1970s.
  11. ^ a b c d e arXiv, FROM MESSIER TO ABELL: 200 YEARS OF SCIENCE WITH GALAXY CLUSTERSPDF (1.09 MB)
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  17. ^ a b Astronomy Now, "XMM discovers monster galaxy cluster", Emily Baldwin, 27 August 2008
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  28. ^ The Most Distant X-ray Massive Galaxy Cluster XMMU J2235.3-2557 z=1.4
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External links

See also

Morphology
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Energetic galaxies
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