List of galaxy groups and clusters

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Abell 2744 galaxy cluster - Hubble Frontier Fields view (7 January 2014) Heic1401a-Abell2744-20140107.jpg
Abell 2744 galaxy cluster - Hubble Frontier Fields view (7 January 2014)

This article lists some galaxy groups and galaxy clusters.

Contents

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.

Clusters exhibiting strong evidence of dark matter

Some clusters exhibiting strong evidence of dark matter.

Galaxy cluster Notes
Bullet Cluster In this collision between two clusters of galaxies, the stars pass between each other unhindered, while the hot, diffuse gas experiences friction and is left behind between the clusters. The gas dominates the visible mass budget of the clusters, being several times more massive than all the stars. Yet the regions with the stars show more gravitational lensing than the gas region, indicating that they are more massive than the gas. Some dark (since we don't see it), collision-less (or it would have been slowed, like the gas) matter is inferred to be present to account for the extra lensing around otherwise low-mass regions. [2]
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. [3]
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. [4] [5]

Named groups and clusters

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

Clusters

Galaxy cluster Origin of nameNotes
Bullet Cluster The cluster is named for the merger of two clusters colliding like a bullet.Also has a systematic designation of 1E 0657-56
El Gordo Named for its size, El Gordo ("the fat one") is the biggest cluster found in the distant universe (at its distance and beyond), at the time of discovery in 2011, with a mass of 3 quadrillion suns. The second most massive galaxy cluster next to El Gordo is RCS2 J2327, a galaxy cluster with the mass of 2 quadrillion suns.Also has a systematic designation of ACT-CL J0102-4915. [6] [7] [8]
Musket Ball Cluster Named in comparison to the Bullet Cluster, as this one is older and slower galaxy cluster merger than the Bullet Cluster.Also has a systematic designation of DLSCL J0916.2+2951. [9]
Pandora's Cluster Named because the cluster resulted from a collision of clusters, which resulted in many different and strange phenomena.Also has a catalogue entry of Abell 2744. [10]

Groups

Galaxy group Origin of nameNotes
Local Group The galaxy group that includes the Milky Way.
Bullet Group Named in comparison with the Bullet Cluster, being of similar formation, except smaller.Also has a systematic catalogue name SL2S J08544-0121. As of 2014, it was the lowest mass object that showed separation between the concentrations of dark matter and baryonic matter in the object. [11] [12]
Burbidge Chain
Copeland Septet Discovered by British astronomer Ralph Copeland in 1874.
Deer Lick Group Coined by Tom 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.Also referred to as the NGC 7331 Group, after the brightest member of the group. [13]
Leo Triplet 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 Cluster.
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 compact group of galaxies lies 160 million light-years away in the Phoenix constellation.
Seyfert's Sextet Named after its discoverer, Carl Seyfert. At the time it appeared to contain six external nebulae. It is also called the NGC 6027 Sextet, after its brightest member.There are actually only five galaxies in the sextet, and only four galaxies in the compact group. One of the galaxies is an ungravitationally bound background object. The other "galaxy" is instead an extension of the interacting system a tidal stream caused by the merger. The group is, therefore, more properly called HCG 79; the name refers to the visual collection and not the group. HCG 79 lies 190 million light-years away in the Serpens Caput constellation.
Stephan's Quintet (Stephan's Quartet)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 group. Thus, the real group is also called Stephan's Quartet.
Wild's Triplet Named after the British-born and Australia-based astronomer Paul Wild (1923–2008), who studied the trio in the early 1950s. [14]
Zwicky's Triplet

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

Groups and clusters visible to the unaided eye

The Local Group contains the largest number of visible galaxies with the naked eye. However, its galaxies are not visually grouped together in the sky, except for the two Magellanic Clouds. The IC342/Maffei Group, the nearest galaxy group, would be visible by the naked eye if it were not obscured by the stars and dust clouds in the Milky Way's spiral arms.

Galaxy group Visible galaxies Notes
Local Group 5Apart from the Milky Way, only 4 galaxies are visible to the naked eye. [15]
Centaurus A/M83 Group 2The Centaurus A galaxy has been spotted with the naked eye by Stephen James O'Meara [16] [17] and M83 has also reportedly been seen with the naked eye. [18]
M81 Group 1Only Bode's Galaxy (M81, NGC 3031) is visible to the naked eye. [15] [19]

Firsts

First discoveredNameDateNotes
Galaxy cluster Virgo Cluster 1784Discovered by Charles Messier. [21]
Galaxy group
Compact groupThe four brightest members of Stephan's Quintet 1877Discovered by Edouard Stephan.
Proto-cluster
Double galaxy Magellanic Clouds antiquity

Extremes

TitleNameDataNotes
Most distant galaxy cluster CL J1001+0220 redshift z=2.506Announced August 2016. [22]
Nearest galaxy cluster Virgo Cluster The Virgo Cluster is at the core of the Virgo Supercluster. The Local Group is a member of the supercluster, but not the cluster.
Most distant galaxy group
Nearest galaxy group Local Group 0 distanceThis is the galaxy group that our galaxy belongs to.
Nearest neighbouring galaxy group IC 342/Maffei Group
Most distant proto-cluster BoRG-58 z~=8 [23]
Nearest proto-cluster
Most distant massive proto-cluster z66OD z=6.585At time of discovery in 2019, the object had 12 members, including Himiko. [24] [25] [26]
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

[27] [28]

Closest groups

Galaxy groups closer than the Virgo Cluster
Galaxy group Distance Redshift (z) Recession velocity (km/s) Notes
Local Group ---Our Galaxy, the Milky Way, belongs to the Local Group.
LGG 104 (IC 342/Maffei Group, IC 342 / Maffei 1 Group, IC 342 Maffei 1-2 Group)0.000868260The 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)3.5  Mpc (11.4  Mly )0.001115334 [29]
Centaurus A/M83 Group (Centarus A Group, M83 Group)3.66  Mpc (11.9  Mly )0.000999299The 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)3.9  Mpc (12.7  Mly )
Canes Venatici Group (Canes Venatici I Group, Canes I Group, M94 Group, NGC 4736 Group, LGG 291)4  Mpc (13.0  Mly )0.001612483
NGC 1023 Group (LGG 70)6.12  Mpc (20.0  Mly )0.002926877
M101 Group (NGC 5457 Group, LGG 371)7.33  Mpc (23.9  Mly )0.001288386
NGC 2997 Group (LGG 180)7.66  Mpc (25.0  Mly )0.002615784
Canes Venatici II Group (Canes II Group)8  Mpc (26.1  Mly )
M51 Group (NGC 5194 Group, LGG 347)9.5  Mpc (31.0  Mly )0.001850555 [29]
Leo Triplet (M66 Group, NGC 3627 Group, LGG 231)10.75  Mpc (35.1  Mly )0.002207662
Leo Group (Leo I Group, M96 Group, NGC 3379 Group, LGG 217)11.66  Mpc (38.0  Mly )0.002267680
Draco Group 12.25  Mpc (40.0  Mly )
LGG 396 (NGC 5866 Group, NGC 5907 Group)0.003020905
Ursa Major Group (Ursa Major I Group, M109 Group, NGC 3992 Group, NGC 3726 Group, LGG 258)16.88  Mpc (55.1  Mly )0.0033881016 [29]
  • Mly represents millions of light-years, a measure of distance.
  • Mpc represents millions of parsecs, a measure of distance (1 Mpc = 3.26 Mly).
  • z represents redshift, a measure of recessional velocity and inferred distance due to cosmological expansion.
    In this very nearby context, however, the observed redshift and recessional velocity are due to the Doppler shifting of the light.
  • Distances are measured from Earth, with Earth being at zero.

Closest clusters

Closest clusters
Galaxy cluster Distance Redshift (z) Recession velocity (km/s) Notes
Virgo Cluster 18  Mpc (59  Mly )0.00381139The Virgo Cluster is at the core of the Virgo Supercluster. The Local Group is a member of the supercluster, but not the cluster. [30]
Fornax Cluster (Abell S 373, AM 0336-353, MCL 52)19  Mpc (62  Mly )0.00461379 [30]
Antlia Cluster (Abell S 636)40.7  Mpc (133  Mly )0.00872608Also called the Antlia Group.
Centaurus Cluster (Abell 3526, Cl 1247-4102)52.4 Mpc0.01103298 [30]
Hydra Cluster (Hydra I Cluster, Abell 1060, Cl 1034-2716)58.3 Mpc0.01143418 [30]
  • Mly represents millions of light-years, a measure of distance.
  • Mpc represents millions of parsecs, 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.

Farthest clusters

Farthest clusters
Galaxy cluster DistanceNotes
No entries yet
  • Mly represents millions of light-years, a measure of distance.
  • Mpc represents millions of parsecs, 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.
Most remote cluster titleholder
Galaxy cluster Date Redshift (z)Recession Velocity
(km/s)
Notes
CL J1001+0220 2016  2.506 [22]
CL J1449+0856
(ClG J1449+0856)
2011–20162.07 [31] [32] [33]
JKCS 041 2009–20111.9
XMMXCS 2215-1738 (XMMXCS 2215.9-1738)2006–20091.45 XMM-XCS 2215-1738 was also the most massive early cluster so far discovered. [34] [35]
ISCS J143809+341419 2005–20061.41 [36] [37]
XMMU J2235.3-2557 20051.393 [38] [39] [40] [41]
RDCS 0848+4453 ( RDCS0848.6+4453, RX J0848+4453, ClG 0848+4453 )1997–1.276ClG 0848+4453 forms a double-cluster supercluster with RDCS J0849+4452 [42] [43] [44] [45] [46]
galaxy cluster around 3C 324 (3C 234 Cluster)1984–1.206At the time, the BCG, 3C324 was the most distant non-quasar galaxy. [47]
Cl 1409+524 1960–19750.461The measurement of 3C295's redshift in 1960 also defined its cluster's position. 3C 295 was also the most distant galaxy of the time. [48] [49]
Abell 732 (fainter Hydra Cluster Cl 0855+0321)1951–19600.261 000 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. [48] [50] [51] [52]
Abell 1930 (Bootes Cluster)1936–19510.1339 000 The BCG of this cluster was also the most distant galaxy of the time. [51] [53]
Gemini Cluster (Abell 568)1932  19360.07523 000 The BCG of this cluster was the most distant galaxy at the time. [53] [54]
WH Christie's Leo Cluster 1931–193219 700 The BCG of this cluster was the most distant galaxy known at the time. [51] [54] [55] [56] [57]
Baede's Ursa Major Cluster 1930–193111 700 The BCG of this cluster was the highest redshift galaxy of the time. [57] [58]
Coma Cluster 1929–19300.0267 800 This cluster's distance was determined by one of the NGC objects lying in it, NGC4860. [58] [59]
Pegasus Group (LGG 473, NGC 7619 Group)19290.0123 779 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. [60]
Cetus Group (Holmberg 45, LGG 27)1921–19290.0061 800  NGC 584 (Dreyer 584) was measured for the redshift to this galaxy group. [60] [61] [62] [63]
Virgo Cluster 1784–192159  Mly (18  Mpc)
z=0.003
1 200 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. [21]
  • Mly represents millions of light-years, a measure of distance.
  • Mpc represents millions of parsecs, 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.

Farthest protoclusters

5 Farthest protoclusters
Galaxy protoclusterDistanceNotes
No entries yet
  • Mly represents millions of light-years, a measure of distance.
  • Mpc represents millions of parsecs, 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.
Most remote protocluster titleholder
Galaxy protoclusterDate Redshift (z)Notes
BoRG-58 2012~ 8 [23]
COSMOS-AzTEC3 2011–5.3Located in Sextans, the cluster appears to contain 11 young small galaxies. [72] [73]
Protocluster around radio-galaxy TN J1338-1942 2002–4.11It was described as the most distant cluster. [74] [75] [76] [77]
Protocluster around 3C 368 1982–1.13 [78]
  • 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.

False clusters

Sometimes clusters are put forward that are not genuine clusters or superclusters. Through the researching of member positions, distances, peculiar velocities, and binding mass, former clusters are sometimes found to be the product of a chance line-of-sight superposition.

Former cluster Notes
Cancer Cluster The Cancer Cluster was found to be a random assortment of galaxy groups, and not a true cluster. [21]
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

See also

Lists of groups and clusters

Related Research Articles

Supercluster Large group of smaller galaxy clusters or galaxy groups

A supercluster is a large group of smaller galaxy clusters or galaxy groups; it is among the largest known structures of the universe. The Milky Way is part of the Local Group galaxy group, which in turn is part of the Virgo Supercluster, which is part of the Laniakea Supercluster. The large size and low density of superclusters means that they, unlike clusters, expand with the Hubble expansion. The number of superclusters in the observable universe is estimated to be 10 million.

Serpens Constellation, straddling the celestial equator, consisting of two non-connected parts (Serpens Caput and Serpens Cauda)

Serpens is a constellation of the northern hemisphere. One of the 48 constellations listed by the 2nd-century astronomer Ptolemy, it remains one of the 88 modern constellations defined by the International Astronomical Union. It is unique among the modern constellations in being split into two non-contiguous parts, Serpens Caput to the west and Serpens Cauda to the east. Between these two halves lies the constellation of Ophiuchus, the "Serpent-Bearer". In figurative representations, the body of the serpent is represented as passing behind Ophiuchus between Mu Serpentis in Serpens Caput and Nu Serpentis in Serpens Cauda.

Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as "stellar nurseries" or "star-forming regions", collapse and form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function. Most stars do not form in isolation but as part of a group of stars referred as star clusters or stellar associations.

Andromeda Galaxy Barred spiral galaxy within the Local Group

The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy approximately 2.5 million light-years from Earth and the nearest major galaxy to the Milky Way. The galaxy's name stems from the area of Earth's sky in which it appears, the constellation of Andromeda, which itself is named after the Ethiopian princess who was the wife of Perseus in Greek mythology.

Lynx (constellation) Constellation in the northern celestial hemisphere

Lynx is a constellation named after the animal, usually observed in the Northern Celestial Hemisphere. The constellation was introduced in the late 17th century by Johannes Hevelius. It is a faint constellation, with its brightest stars forming a zigzag line. The orange giant Alpha Lyncis is the brightest star in the constellation, and the semiregular variable star Y Lyncis is a target for amateur astronomers. Six star systems have been found to contain planets. Those of 6 Lyncis and HD 75898 were discovered by the Doppler method; those of XO-2, XO-4, XO-5 and WASP-13 were observed as they passed in front of the host star.

Abell 2218 Galaxy cluster in the constellation Draco

Abell 2218 is a cluster of galaxies about 2 billion light-years away in the constellation Draco.

Messier 32 Elliptical galaxy in the constellation Andromeda

Messier 32 is a dwarf "early-type" galaxy about 2,650,000 light-years (810,000 pc) from our star system, appearing in the constellation Andromeda. M32 is a satellite galaxy of the Andromeda Galaxy (M31) and was discovered by Guillaume Le Gentil in 1749. Its true size is about 34 of the radius of the Sun from the local galactic centre, 6,300–6,700 light-years (1,900–2,100 pc) at its quite unpronounced widest.

Redshift quantization, also referred to as redshift periodicity, redshift discretization, preferred redshifts and redshift-magnitude bands, is the hypothesis that the redshifts of cosmologically distant objects tend to cluster around multiples of some particular value. In standard inflationary cosmological models, the redshift of cosmological bodies is ascribed to the expansion of the universe, with greater redshift indicating greater cosmic distance from the Earth. This is referred to as cosmological redshift. Ruling out errors in measurement or analysis, quantized redshift of cosmological objects would either indicate that they are physically arranged in a quantized pattern around the Earth, or that there is an unknown mechanism for redshift unrelated to cosmic expansion, referred to as "intrinsic redshift" or "non-cosmological redshift".

Lyman-alpha blob

In astronomy, a Lyman-alpha blob (LAB) is a huge concentration of a gas emitting the Lyman-alpha emission line. LABs are some of the largest known individual objects in the Universe. Some of these gaseous structures are more than 400,000 light years across. So far they have only been found in the high-redshift universe because of the ultraviolet nature of the Lyman-alpha emission line. Since the Earth's atmosphere is very effective at filtering out UV photons, the Lyman-alpha photons must be redshifted in order to be transmitted through the atmosphere.

NGC 4536 Intermediate spiral galaxy in the constellation Virgo

NGC 4536 is an intermediate spiral galaxy in the constellation Virgo located about 10° south of the midpoint of the Virgo cluster. However, it is not considered a member of the cluster but is a member of the Virgo II Groups which form a southern extension of the Virgo Cluster. The morphological classification in the De Vaucouleurs system is SAB(rs)bc, which indicates it is a weakly barred spiral galaxy with a hint of an inner ring structure plus moderate to loosely wound arms. It does not have a classical bulge around the nucleus.

Galaxy filament Largest structures in the universe, made of galaxies

In cosmology, galaxy filaments are the largest known structures in the universe, consisting of walls of gravitationally bound galaxy superclusters. These massive, thread-like formations can reach 80 megaparsecs h−1 and form the boundaries between large voids.

NGC 4921 Barred spiral galaxy in the constellation Coma Berenices

NGC 4921 is a barred spiral galaxy in the Coma Cluster, located in the constellation Coma Berenices. It is about 320 million light-years from Earth. The galaxy has a nucleus with a bar structure that is surrounded by a distinct ring of dust that contains recently formed, hot blue stars. The outer part consists of unusually smooth, poorly distinguished spiral arms.

MACS J0647.7+7015 Galaxy cluster in the constellation Camelopardalis

MACS J0647.7+7015 is a galaxy cluster with a redshift z = 0.592, located at J2000.0 right ascension 06h 47m 42s declination +70° 15′. It lies between the Big Dipper and Little Dipper in the constellation Camelopardalis. It is part of a sample of 12 extreme galaxy clusters at z > 0.5 discovered by the MAssive Cluster Survey (MACS).

NGC 4494 Elliptical galaxy in the constellation Coma Berenices

NGC 4494 is an elliptical galaxy located in the constellation Coma Berenices. It is located at a distance of circa 45 million light years from Earth, which, given its apparent dimensions, means that NGC 4494 is about 60,000 light years across. It was discovered by William Herschel in 1785.

NGC 3860 Spiral galaxy in the constellation Leo

NGC 3860 is a spiral galaxy located about 340 million light-years away in the constellation Leo. NGC 3860 was discovered by astronomer William Herschel on April 27, 1785. The galaxy is a member of the Leo Cluster and is a low-luminosity AGN (LLAGN). Gavazzi et al. however classified NGC 3860 as a strong AGN which may have been triggered by a supermassive black hole in the center of the galaxy.

NGC 4278 Elliptical galaxy in the constellation Coma Berenices

NGC 4278 is an elliptical galaxy located in the constellation Coma Berenices. It is located at a distance of circa 55 million light years from Earth, which, given its apparent dimensions, means that NGC 4278 is about 65,000 light years across. It was discovered by William Herschel on March 13, 1785. NGC 4278 is part of the Herschel 400 Catalogue and can be found about one and 3/4 of a degree northwest of Gamma Comae Berenices even with a small telescope.

References

  1. Clavin, Whitney; Jenkins, Ann; Villard, Ray (7 January 2014). "NASA's Hubble and Spitzer Team up to Probe Faraway Galaxies". NASA . Retrieved 8 January 2014.
  2. "Galaxy Collision Separates Out the Dark Matter". Universe Today. 2006-08-21.
  3. "Galaxy Cluster Collision Creates a Dark Matter Core". Universe Today. 2007-08-16.
  4. "Ring of Dark Matter Discovered Around a Galaxy Cluster". Universe Today. 2007-05-15.
  5. SIMBAD, "ClG 0024+17"
  6. Schilling, Govert (12 January 2012). "When Galaxies Crash". ScienceNOW. Archived from the original on 2012-01-29.
  7. "Humongous 'El Gordo' galaxy cluster packs mass of 2 quadrillion stars". Christian Science Monitor. 2012-01-11.
  8. NASA, "El Gordo Galaxy Cluster", 10 January 2012 (accessed 7 July 2012)
  9. "Discovery of the Musket Ball Cluster, a system of colliding galaxy clusters". Science Daily.
  10. ESO, "A Galactic Crash Investigation", 22 June 2011 (accessed 7 July 2012)
  11. XMM-Newton (6 June 2014). "Cosmic collision in the Bullet Group". European Space Agency.
  12. Gastaldello, F.; et al. (2014). "Dark matter–baryons separation at the lowest mass scale: The Bullet Group". Monthly Notices of the Royal Astronomical Society: Letters. 442: L76–L80. arXiv: 1404.5633 . Bibcode:2014MNRAS.442L..76G. doi:10.1093/mnrasl/slu058.
  13. Saratoga Skies, "NGC 7331 (Deer Lick Group and Stephan's Quintet)", Jim Solomon (accessed 7 May 2009)
  14. "Wild's Triplet". Oxford Reference . Retrieved 13 October 2018.
  15. 1 2 Stephen Uitti (27 May 2005). "Farthest Naked Eye Object". Uitti.net. Retrieved 2008-11-01.
  16. "Aintno Catalog".
  17. Inglis, Mike (2007). "Galaxies". Patrick Moore's Practical Astronomy Series: 157–189. doi:10.1007/978-1-84628-736-7_4. ISBN   978-1-85233-890-9.
  18. Inglis, Mike (2007). "Galaxies". Patrick Moore's Practical Astronomy Series: 157–189. doi:10.1007/978-1-84628-736-7_4. ISBN   978-1-85233-890-9.
  19. SEDS, Messier 81
  20. A. Schwope (2013). "Galaxy Clusters". Arches Project.
  21. 1 2 3 Biviano, Andrea; et al. (2000). "From Messier to Abell: 200 years of science with galaxy clusters". In Florence Durret; Daniel Gerbal (eds.). Constructing the Universe with Clusters of Galaxies, IAP 2000 meeting, Paris, France, July 2000. Constructing the Universe with Clusters of Galaxies. p. 1. arXiv: astro-ph/0010409 . Bibcode:2000cucg.confE...1B.
  22. 1 2 Wang, Tao; et al. (2016). "Discovery of a galaxy cluster with a violently starbursting core at z=2.506". The Astrophysical Journal. 828 (1): 56. arXiv: 1604.07404 . Bibcode:2016ApJ...828...56W. doi:10.3847/0004-637X/828/1/56. S2CID   8771287.
  23. 1 2 SpaceTelescope.org (ESA), "Hubble Spies Building Blocks of Most Distant Galaxy Cluster", 10 January 2012 (accessed March 2012)
  24. National Institutes of Natural Sciences (27 September 2019). "Oldest galaxy protocluster forms 'queen's court'". ScienceDaily.
  25. Yuichi Harikane, Masami Ouchi, Yoshiaki Ono, Seiji Fujimoto, Darko Donevski, Takatoshi Shibuya, Andreas L. Faisst, Tomotsugu Goto, Bunyo Hatsukade, Nobunari Kashikawa, Kotaro Kohno, Takuya Hashimoto, Ryo Higuchi, Akio K. Inoue, Yen-Ting Lin, Crystal L. Martin, Roderik Overzier, Ian Smail, Jun Toshikawa, Hideki Umehata, Yiping Ao, Scott Chapman, David L. Clements, Myungshin Im, Yipeng Jing, Toshihiro Kawaguchi, Chien-Hsiu Lee, Minju M. Lee, Lihwai Lin, Yoshiki Matsuoka, Murilo Marinello, Tohru Nagao, Masato Onodera, Sune Toft, Wei-Hao Wang (25 February 2019). "SILVERRUSH. VIII. Spectroscopic Identifications of Early Large Scale Structures with Protoclusters Over 200 Mpc at z~6-7: Strong Associations of Dusty Star-Forming Galaxies". Astrophysical Journal (published 30 September 2019). 883 (2): 142. arXiv: 1902.09555 . Bibcode:2019arXiv190209555H. doi:10.3847/1538-4357/ab2cd5. S2CID   118955475.CS1 maint: uses authors parameter (link)
  26. "Astronomers spot oldest galactic protocluster, a giant of the early universe". UPI. 27 September 2019.
  27. "080827 XMM discovers monster galaxy cluster". Astronomy Now.
  28. Gitti, M.; et al. (2004). "XMM-Newtonobservation of the most X-ray-luminous galaxy cluster RX J1347.5-1145". Astronomy & Astrophysics. 427: L9–L12. arXiv: astro-ph/0409627 . Bibcode:2004A&A...427L...9G. doi:10.1051/0004-6361:200400086. S2CID   119342554.
  29. 1 2 3 Hayden Planetarium, Galaxy Clusters and Superclusters Archived 2008-08-19 at the Wayback Machine
  30. 1 2 3 4 Hayden Planetarium, The 2MASS Galaxies Archived 2008-08-28 at the Wayback Machine
  31. Gobat, R.; et al. (2011). "A mature cluster with X-ray emission at z= 2.07". Astronomy & Astrophysics. 526: A133. arXiv: 1011.1837 . Bibcode:2011A&A...526A.133G. doi:10.1051/0004-6361/201016084. S2CID   39625321.
  32. ABC News (Australia), "Astronomers find old heads in a young crowd", Stuart Gary, 10 March 2011
  33. SIMBAD, "ClG J1449+0856"
  34. XCS, "XMM Cluster Survey - discovering the most distant galaxy clusters" (PDF).[ permanent dead link ], April 2006
  35. University of Portsmith - Institute of Cosmology and Gravitation; ICG in team that detects the most distant galaxy cluster Archived 2007-08-12 at the Wayback Machine , 15 June 2006
  36. NASA - Spitzer Space Telescope, Great Galactic Buddies Archived 2008-05-11 at the Wayback Machine
  37. Stanford, S. A.; et al. (2005). "An IR-selected Galaxy Cluster at z = 1.41". The Astrophysical Journal. 634 (2): L129–L132. arXiv: astro-ph/0510655 . Bibcode:2005ApJ...634L.129S. doi:10.1086/499045. S2CID   18016845.
  38. 1 2 New Scientist, Most distant galaxy cluster yet is revealed, 08:00 02 March 2005
  39. The Most Distant X-ray Massive Galaxy Cluster XMMU J2235.3-2557 z=1.4 Archived 2008-02-09 at the Wayback Machine
  40. 1 2 MAX-PLANCK-INSTITUT FÜR EXTRATERRESTRISCHE PHYSIK, GARCHING, GERMANY; DEPARTMENT OF ASTRONOMY, UNIVERSITY OF MICHIGAN, ANN ARBOR, USA; ESO, ASTROPHYSIKALISCHES INSTITUT, POTSDAM, GERMANY; "GALAXY CLUSTER ARCHAEOLOGY" (PDF). Archived from the original (PDF) on 2006-06-22. ; HANS BÖHRINGER, CHRISTOPHER MULIS, PIERO ROSATI, GEORG LAMER, RENE FASSBENDER, AXEL SCHWOPE, PETER SCHUECKER
  41. ESO Press Release 04/05; Surprise Discovery of Highly Developed Structure in the Young Universe Archived 2008-06-11 at the Wayback Machine ; 2 March 2005
  42. 1 2 Rosati, P.; et al. (2004). "ChandraandXMM-Newton Observations of RDCS 1252.9-2927, A Massive Cluster atz=1.24". The Astronomical Journal. 127 (1): 230–238. arXiv: astro-ph/0309546 . Bibcode:2004AJ....127..230R. doi:10.1086/379857. S2CID   119038061.
  43. 1 2 Stanford, S. A.; Holden, Brad; Rosati, Piero; Eisenhardt, Peter R.; Stern, Daniel; Squires, Gordon; Spinrad, Hyron (2002). "An X-Ray–Selected Galaxy Cluster at [ITAL][CLC]z[/CLC][/ITAL] = 1.11 in the [ITAL]ROSAT[/ITAL] Deep Cluster Survey". The Astronomical Journal. 123 (2): 619–626. arXiv: astro-ph/0110709 . doi:10.1086/338442. S2CID   14519831.
  44. Stanford, S. A.; et al. (2001). "The Intracluster Medium inz > 1 Galaxy Clusters". The Astrophysical Journal. 552 (2): 504–507. arXiv: astro-ph/0012250 . Bibcode:2001ApJ...552..504S. doi:10.1086/320583. S2CID   5109074.
  45. Stanford, S. A.; et al. (1997). "An IR-Selected Galaxy Cluster at ζ=1.27". The Astronomical Journal. 114: 2232. arXiv: astro-ph/9709057 . Bibcode:1997AJ....114.2232S. doi:10.1086/118643. S2CID   117163515.
  46. 1 2 Rosati, Piero; et al. (1999). "An X-Ray–Selected Galaxy Cluster at [CLC][ITAL]z[/ITAL][/CLC] = 1.26". The Astronomical Journal. 118: 76–85. arXiv: astro-ph/9903381 . Bibcode:1999AJ....118...76R. doi:10.1086/300934. S2CID   2560006.
  47. Spinrad, H.; Djorgovski, S. (1984). "3C 324 - an extremely distant cluster radio galaxy" (PDF). The Astrophysical Journal. 280: L9. Bibcode:1984ApJ...280L...9S. doi:10.1086/184258.
  48. 1 2 3 Sandage, Allan (1961). "The Ability of the 200-INCH Telescope to Discriminate Between Selected World Models". The Astrophysical Journal. 133: 355. Bibcode:1961ApJ...133..355S. doi:10.1086/147041.
  49. Palomar Skies, Pushing the limit, Saturday, March 29, 2008
  50. "1053 May 8 meeting of the Royal Astronomical Society". The Observatory. 73: 97. 1953. Bibcode:1953Obs....73...97.
  51. 1 2 3 Annu. Rev. Astron. Astrophys. 1988. 26: 561-630; OBSERVATIONAL TESTS OF WORLD MODELS - 6. THE m(z) HUBBLE DIAGRAM; Allan Sandage
  52. Merrill, Paul W. (1958). "From Atoms to Galaxies". Leaflet of the Astronomical Society of the Pacific. 7 (349): 393. Bibcode:1958ASPL....7..393M.
  53. 1 2 Humason, M. L. (1936). "The Apparent Radial Velocities of 100 Extra-Galactic Nebulae". The Astrophysical Journal. 83: 10. Bibcode:1936ApJ....83...10H. doi:10.1086/143696.
  54. 1 2 Chant, C. A. (1932). "Notes and Queries (Doings at Mount Wilson-Ritchey's Photographic Telescope-Infra-red Photographic Plates)". Journal of the Royal Astronomical Society of Canada. 26: 180. Bibcode:1932JRASC..26..180C.
  55. Humason, Milton L. (1931). "Apparent Velocity-Shifts in the Spectra of Faint Nebulae". The Astrophysical Journal. 74: 35. Bibcode:1931ApJ....74...35H. doi:10.1086/143287.
  56. Hubble, Edwin; Humason, Milton L. (1931). "The Velocity-Distance Relation among Extra-Galactic Nebulae". The Astrophysical Journal. 74: 43. Bibcode:1931ApJ....74...43H. doi:10.1086/143323.
  57. 1 2 Humason, M. L. (1931). "The Large Apparent Velocities of Extra-Galactic Nebulae". Leaflet of the Astronomical Society of the Pacific. 1 (37): 149. Bibcode:1931ASPL....1..149H.
  58. 1 2 Humason, M. L. (1930). "The Rayton short-focus spectrographic objective". The Astrophysical Journal. 71: 351. Bibcode:1930ApJ....71..351H. doi:10.1086/143255.
  59. "The Berkeley Meeting of the Astronomical Society of the Pacific, June 20-21, 1929". Publications of the Astronomical Society of the Pacific. 41 (242): 244. 1929. Bibcode:1929PASP...41..244.. doi: 10.1086/123945 .
  60. 1 2 From the Proceedings of the National Academy of Sciences; Volume 15 : March 15, 1929 : Number 3; THE LARGE RADIAL VELOCITY OF N. G. C. 7619; January 17, 1929
  61. Bailey, S. I. (1920). "Comet Skjellerup". Harvard College Observatory Bulletin. 739: 1. Bibcode:1920BHarO.739....1B.
  62. New York Times, DREYER NEBULA NO. 584 INCONCEIVABLY DISTANT; Dr. Slipher Says the Celestial Speed Champion Is 'Many Millions of Light Years' Away.; January 19, 1921, Wednesday
  63. New York Times, NEBULA DREYER BREAKS ALL SKY SPEED RECORDS; Portion of the Constellation of Cetus Is Rushing Along at Rate of 1,240 Miles a Second.; January 18, 1921, Tuesday
  64. Liu, Michael C.; et al. (2000). "Extremely Red Objects in the Field of QSO 1213-0017: A Galaxy Concentration at Z=1.31". The Astronomical Journal. 119 (6): 2556–2570. arXiv: astro-ph/0002443 . Bibcode:2000AJ....119.2556L. doi:10.1086/301399. S2CID   10133168.
  65. Fabian, A. C.; et al. (2001). "Chandra detection of the intracluster medium around 3C 294 at z = 1.786" (PDF). Monthly Notices of the Royal Astronomical Society. 322 (1): L11–L15. arXiv: astro-ph/0101478 . Bibcode:2001MNRAS.322L..11F. doi:10.1046/j.1365-8711.2001.04361.x. S2CID   16084344. Archived from the original (PDF) on 2011-09-29. (176 KB); 2001 January 25
  66. Dressler, A. (1993). "The Spectra and Morphology of Galaxies in High-Redshift Clusters". Observational Cosmology. 51: 225. Bibcode:1993ASPC...51..225D.
  67. European Space Agency; Peering Far Back in Time to Uncover the Secrets of Galaxy Evolution; 01 Dec 1992
  68. Dressler, Alan (1993). "Galaxies Far Away and Long Ago". Sky and Telescope. 85 (4): 22. Bibcode:1993S&T....85...22D.
  69. Dressler, Alan; Oemler, Augustus; Gunn, James E.; Butcher, Harvey (1993). "A Cluster of Nascent Galaxies at Z = 2?". The Astrophysical Journal. 404: L45. Bibcode:1993ApJ...404L..45D. doi:10.1086/186740.
  70. NED, Searching NED for object "3C 123"
  71. Spinrad, H. (1975). "3C 123: A distant first-ranked cluster galaxy at z = 0.637". The Astrophysical Journal. 199: L3. Bibcode:1975ApJ...199L...3S. doi:10.1086/181835.
  72. Naeye, Robert (13 January 2011). "The Most Distant Galaxy Cluster". Sky & Telescope. Archived from the original on 2013-02-02.
  73. BBC News, "Galaxy clusters' ancient light shows young cosmic city", Jason Palmer, 13 January 2011
  74. Associated Press, Oldest, most distant galaxy clusters found, 4:37 p.m. ET, Mon., Jan. 5, 2004
  75. Venemans, B. P. (2002). "The Most Distant Structure of Galaxies Known: A Protocluster at [CLC][ITAL]z[/ITAL][/CLC] = 4.1". The Astrophysical Journal. 569: L11–L14. doi: 10.1086/340563 .
  76. Science, Oldest Galaxy Cluster Found, 12 April 2002
  77. 1 2 ESO Press Release 07/02; Most Distant Group of Galaxies Known in the Universe Archived 2008-09-16 at the Wayback Machine ; 9 April 2002
  78. Publications of the Astronomical Society of the Pacific, vol. 94, June–July 1982, p. 397-403. Redshifts and spectroscopy of very distant radio galaxies with strong emission lines 1982PASP...94..397S
  79. ESO Press Release 03/02; UVES Investigates the Environment of a Very Remote Galaxy Archived 2008-10-02 at the Wayback Machine ; 11 March 2002