Astronomy:List of galaxy groups and clusters
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.
|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.|
|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.|
|Abell 2142||A collision between two massive, X-ray luminous galaxy clusters.|
(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.|
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.
|Galaxy cluster||Origin of name||Notes|
|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. 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.|
|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.|
|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.|
|Galaxy group||Origin of name||Notes|
|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.|
|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.|
|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.|
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||5||Apart from the Milky Way, only 4 galaxies are visible to the naked eye.|
|Centaurus A/M83 Group||2||The Centaurus A galaxy has been spotted with the naked eye by Stephen James O'Meara  and M83 has also reportedly been seen with the naked eye.|
|M81 Group||1||Only Bode's Galaxy (M81, NGC 3031) is visible to the naked eye.|
- No galaxy cluster is visible to the unaided eye.
|Galaxy cluster||Virgo Cluster||1784||Discovered by Charles Messier.|
|Compact group||The four brightest members of Stephan's Quintet||1877||Discovered by Edouard Stephan.|
|Double galaxy||Magellanic Clouds||antiquity|
|Most distant galaxy cluster||CL J1001+0220||redshift z=2.506||Announced August 2016.|||
|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 distance||This 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|||
|Most distant massive proto-cluster||z66OD||z=6.585||At time of discovery in 2019, the object had 12 members, including Himiko.|||
|Least massive galaxy group|
|Most massive galaxy cluster||RX J1347.5-1145||mass= 2.0 ± 0.4 × 1015 MSun||
|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)||0.000868||260||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)||3.5 Mpc (11.4 Mly)||0.001115||334|||
|Centaurus A/M83 Group (Centarus A Group, M83 Group)||3.66 Mpc (11.9 Mly)||0.000999||299||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)||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)||0.001612||483|
|NGC 1023 Group (LGG 70)||6.12 Mpc (20.0 Mly)||0.002926||877|
|M101 Group (NGC 5457 Group, LGG 371)||7.33 Mpc (23.9 Mly)||0.001288||386|
|NGC 2997 Group (LGG 180)||7.66 Mpc (25.0 Mly)||0.002615||784|
|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)||0.001850||555|||
|Leo Triplet (M66 Group, NGC 3627 Group, LGG 231)||10.75 Mpc (35.1 Mly)||0.002207||662|
|Leo Group (Leo I Group, M96 Group, NGC 3379 Group, LGG 217)||11.66 Mpc (38.0 Mly)||0.002267||680|
|Draco Group||12.25 Mpc (40.0 Mly)|
|LGG 396 (NGC 5866 Group, NGC 5907 Group)||0.003020||905|
|Ursa Major Group (Ursa Major I Group, M109 Group, NGC 3992 Group, NGC 3726 Group, LGG 258)||16.88 Mpc (55.1 Mly)||0.003388||1016|||
|Galaxy cluster||Distance||Redshift (z)||Recession velocity (km/s)||Notes|
|Virgo Cluster||18 Mpc (59 Mly)||0.0038||1139||The Virgo Cluster is at the core of the Virgo Supercluster. The Local Group is a member of the supercluster, but not the cluster.|
|Fornax Cluster (Abell S 373, AM 0336-353, MCL 52)||19 Mpc (62 Mly)||0.0046||1379|||
|Antlia Cluster (Abell S 636)||40.7 Mpc (133 Mly)||0.0087||2608||Also called the Antlia Group.|
|Centaurus Cluster (Abell 3526, Cl 1247-4102)||0.0110||3298|||
|Hydra Cluster (Hydra I Cluster, Abell 1060, Cl 1034-2716)||0.0114||3418|||
|No entries yet|
|Galaxy cluster||Date||Redshift (z)||Recession Velocity
|CL J1001+0220||2016 −||2.506|||
|XMMXCS 2215-1738 (XMMXCS 2215.9-1738)||2006–2009||1.45||XMM-XCS 2215-1738 was also the most massive early cluster so far discovered.|
|RDCS 0848+4453 ( RDCS0848.6+4453, RX J0848+4453, ClG 0848+4453 )||1997–||1.276||ClG 0848+4453 forms a double-cluster supercluster with RDCS J0849+4452 |
|galaxy cluster around 3C 324 (3C 234 Cluster)||1984–||1.206||At the time, the BCG, 3C324 was the most distant non-quasar galaxy.|
|Cl 1409+524||1960–1975||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.|
|Abell 732 (fainter Hydra Cluster Cl 0855+0321)||1951–1960||0.2||61 000||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.|
|Abell 1930 (Bootes Cluster)||1936–1951||0.13||39 000||The BCG of this cluster was also the most distant galaxy of the time.|
|Gemini Cluster (Abell 568)||1932 − 1936||0.075||23 000||The BCG of this cluster was the most distant galaxy at the time.|
|WH Christie's Leo Cluster||1931–1932||19 700||The BCG of this cluster was the most distant galaxy known at the time.|
|Baede's Ursa Major Cluster||1930–1931||11 700||The BCG of this cluster was the highest redshift galaxy of the time.|
|Coma Cluster||1929–1930||0.026||7 800||This cluster's distance was determined by one of the NGC objects lying in it, NGC4860.|
|Pegasus Group (LGG 473, NGC 7619 Group)||1929||0.012||3 779||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.|
|Cetus Group (Holmberg 45, LGG 27)||1921–1929||0.006||1 800||NGC 584 (Dreyer 584) was measured for the redshift to this galaxy group.|
|Virgo Cluster||1784–1921||59 Mly (18 Mpc)
|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.|
- In 2003 RDCS 1252-29 (RDCS1252.9–2927) at z=1.237, was found to be the most distant rich cluster, which lasted until 2005.
- In 2000, a cluster was announced in the field of quasar QSO 1213-0017 at z=1.31 (the quasar lies at z=2.69) 
- In 1999, cluster RDCS J0849+4452 (RX J0849+4452, RXJ0848.9+4452) was found at z=1.261 
- In 1995 and 2001, the cluster around 3C 294 was announced, at z=1.786 
- In 1992, observations of the field of cluster Cl 0939+4713 found what appears to be a background cluster near a quasar, also in the background. The quasar was measured at z=2.055 and it was assumed that the cluster would be as well.
- In 1975, 3C 123 and its galaxy cluster was incorrectly determined to lie at z=0.637 (actually z=0.218) 
- In 1958, cluster Cl 0024+1654 and Cl 1447+2619 were estimated to have redshifts of z=0.29 and z=0.35 respectively. However, they were not spectroscopically determined.
|No entries yet|
|Galaxy protocluster||Date||Redshift (z)||Notes|
|COSMOS-AzTEC3||2011–||5.3||Located in Sextans, the cluster appears to contain 11 young small galaxies.|
|Protocluster around radio-galaxy TN J1338-1942||2002–||4.11||It was described as the most distant cluster.|
|Protocluster around 3C 368||1982–||1.13|||
- In 2002, a very large, very rich protocluster, or the most distant protosupercluster was found in the field of galaxy cluster MS 1512+36, around the gravitationally lensed galaxy MS 1512-cB58, at z=2.724 
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.
|Cancer Cluster||The Cancer Cluster was found to be a random assortment of galaxy groups, and not a true cluster.|
|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
- Catalogue of Galaxies and Clusters of Galaxies
- Hickson Compact Group
- List of Abell clusters
- List of galaxy superclusters
- Lyons Groups of Galaxies
- Virgo Supercluster
- Clavin, Whitney; Jenkins, Ann; Villard, Ray (7 January 2014). "NASA's Hubble and Spitzer Team up to Probe Faraway Galaxies". NASA. http://www.jpl.nasa.gov/news/news.php?release=2014-007. Retrieved 8 January 2014.
- "Galaxy Collision Separates Out the Dark Matter". 2006-08-21. http://www.universetoday.com/2006/08/21/galaxy-collision-separates-out-the-dark-matter/.
- "Galaxy Cluster Collision Creates a Dark Matter Core". 2007-08-16. http://www.universetoday.com/2007/08/16/galaxy-cluster-collision-creates-a-dark-matter-core/.
- "Ring of Dark Matter Discovered Around a Galaxy Cluster". 2007-05-15. http://www.universetoday.com/2007/05/15/ring-of-dark-matter-discovered-around-a-galaxy-cluster/.
- SIMBAD, "ClG 0024+17"
- Schilling, Govert (12 January 2012). "When Galaxies Crash". http://news.sciencemag.org/sciencenow/2012/01/when-galaxies-crash.html.
- "Humongous 'El Gordo' galaxy cluster packs mass of 2 quadrillion stars". Christian Science Monitor. 2012-01-11. http://www.csmonitor.com/Science/2012/0111/Humongous-El-Gordo-galaxy-cluster-packs-mass-of-2-quadrillion-stars.
- NASA, "El Gordo Galaxy Cluster", 10 January 2012 (accessed 7 July 2012)
- "Discovery of the Musket Ball Cluster, a system of colliding galaxy clusters". https://www.sciencedaily.com/releases/2012/04/120412113714.htm.
- ESO, "A Galactic Crash Investigation", 22 June 2011 (accessed 7 July 2012)
- XMM-Newton (6 June 2014). "Cosmic collision in the Bullet Group". European Space Agency. http://sci.esa.int/xmm-newton/54116-cosmic-collision-in-the-bullet-group/.
- Gastaldello, F. (2014). "Dark matter–baryons separation at the lowest mass scale: The Bullet Group". Monthly Notices of the Royal Astronomical Society: Letters 442: L76–L80. doi:10.1093/mnrasl/slu058. Bibcode: 2014MNRAS.442L..76G.
- Saratoga Skies, "NGC 7331 (Deer Lick Group and Stephan's Quintet)", Jim Solomon (accessed 7 May 2009)
- "Wild's Triplet". http://www.oxfordreference.com/view/10.1093/oi/authority.20110803122508142. Retrieved 13 October 2018.
- 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.
- "Aintno Catalog". http://astronomy-mall.com/Adventures.In.Deep.Space/aintno.htm.
- 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. https://archive.org/details/astrophysicsisea0000ingl/page/157.
- 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. https://archive.org/details/astrophysicsisea0000ingl/page/157.
- SEDS, Messier 81
- A. Schwope (2013). "Galaxy Clusters". Arches Project. http://www.arches-fp7.eu/depot/outreach/html/Clusters.html.
- Biviano, Andrea (2000). "From Messier to Abell: 200 years of science with galaxy clusters". in Florence Durret. Constructing the Universe with Clusters of Galaxies, IAP 2000 meeting, Paris, France, July 2000. 1. Bibcode: 2000cucg.confE...1B.
- Wang, Tao (2016). "Discovery of a galaxy cluster with a violently starbursting core at z=2.506". The Astrophysical Journal 828 (1): 56. doi:10.3847/0004-637X/828/1/56. Bibcode: 2016ApJ...828...56W.
- SpaceTelescope.org (ESA), "Hubble Spies Building Blocks of Most Distant Galaxy Cluster", 10 January 2012 (accessed March 2012)
- National Institutes of Natural Sciences (27 September 2019). "Oldest galaxy protocluster forms 'queen's court'". ScienceDaily. https://www.sciencedaily.com/releases/2019/09/190927074941.htm.
- 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 883: 142. 30 September 2019. doi:10.3847/1538-4357/ab2cd5. Bibcode: 2019arXiv190209555H.
- "Astronomers spot oldest galactic protocluster, a giant of the early universe". UPI. 27 September 2019. https://www.upi.com/Science_News/2019/09/27/Astronomers-spot-oldest-galactic-protocluster-a-giant-of-the-early-universe/1391569591666/.
- "080827 XMM discovers monster galaxy cluster". http://astronomynow.com/080827XMMdiscoversmonstergalaxycluster.html.
- Gitti, M. (2004). "XMM-Newtonobservation of the most X-ray-luminous galaxy cluster RX J1347.5-1145". Astronomy & Astrophysics 427: L9–L12. doi:10.1051/0004-6361:200400086. Bibcode: 2004A&A...427L...9G.
- Hayden Planetarium, Galaxy Clusters and Superclusters
- Hayden Planetarium, The 2MASS Galaxies
- Gobat, R. (2011). "A mature cluster with X-ray emission at z= 2.07". Astronomy & Astrophysics 526: A133. doi:10.1051/0004-6361/201016084. Bibcode: 2011A&A...526A.133G.
- ABC News (Australia), "Astronomers find old heads in a young crowd", Stuart Gary, 10 March 2011
- SIMBAD, "ClG J1449+0856"
- XCS, "XMM Cluster Survey - discovering the most distant galaxy clusters". http://www.astro.ljmu.ac.uk/~xcs/Publications/XCS_NAM06.pdf. [yes|permanent dead link|dead link}}], April 2006
- University of Portsmith - Institute of Cosmology and Gravitation ; ICG in team that detects the most distant galaxy cluster , 15 June 2006
- NASA - Spitzer Space Telescope, Great Galactic Buddies
- Stanford, S. A. (2005). "An IR-selected Galaxy Cluster at z = 1.41". The Astrophysical Journal 634 (2): L129–L132. doi:10.1086/499045. Bibcode: 2005ApJ...634L.129S.
- New Scientist, Most distant galaxy cluster yet is revealed, 08:00 02 March 2005
- The Most Distant X-ray Massive Galaxy Cluster XMMU J2235.3-2557 z=1.4
- 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". Archived from the original on 2006-06-22. https://web.archive.org/web/20060622085640/http://www.astro.lsa.umich.edu/~cmullis/papers/Boehringer_et_al_2005.pdf. ; HANS BÖHRINGER, CHRISTOPHER MULIS, PIERO ROSATI, GEORG LAMER, RENE FASSBENDER, AXEL SCHWOPE, PETER SCHUECKER
- ESO Press Release 04/05 ; Surprise Discovery of Highly Developed Structure in the Young Universe ; 2 March 2005
- Rosati, P. (2004). "ChandraandXMM-Newton Observations of RDCS 1252.9-2927, A Massive Cluster atz=1.24". The Astronomical Journal 127: 230–238. doi:10.1086/379857.
- 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. doi:10.1086/338442.
- Stanford, S. A. (2001). "The Intracluster Medium inz > 1 Galaxy Clusters". The Astrophysical Journal 552 (2): 504–507. doi:10.1086/320583.
- Stanford, S. A. (1997). "An IR-Selected Galaxy Cluster at ζ=1.27". The Astronomical Journal 114: 2232. doi:10.1086/118643. Bibcode: 1997AJ....114.2232S.
- Rosati, Piero (1999). "An X-Ray–Selected Galaxy Cluster at [CLC][ITAL]z[/ITAL][/CLC] = 1.26". The Astronomical Journal 118: 76–85. doi:10.1086/300934. Bibcode: 1999AJ....118...76R.
- Spinrad, H.; Djorgovski, S. (1984). "3C 324 - an extremely distant cluster radio galaxy". The Astrophysical Journal 280: L9. doi:10.1086/184258. Bibcode: 1984ApJ...280L...9S. https://authors.library.caltech.edu/97539/1/1984ApJ___280L___9S.pdf.
- Sandage, Allan (1961). "The Ability of the 200-INCH Telescope to Discriminate Between Selected World Models". The Astrophysical Journal 133: 355. doi:10.1086/147041. Bibcode: 1961ApJ...133..355S.
- Palomar Skies, Pushing the limit, Saturday, March 29, 2008
- "1053 May 8 meeting of the Royal Astronomical Society". The Observatory 73: 97. 1953. Bibcode: 1953Obs....73...97..
- Annu. Rev. Astron. Astrophys. 1988. 26: 561-630 ; OBSERVATIONAL TESTS OF WORLD MODELS - 6. THE m(z) HUBBLE DIAGRAM ; Allan Sandage
- Merrill, Paul W. (1958). "From Atoms to Galaxies". Leaflet of the Astronomical Society of the Pacific 7 (349): 393. Bibcode: 1958ASPL....7..393M.
- Humason, M. L. (1936). "The Apparent Radial Velocities of 100 Extra-Galactic Nebulae". The Astrophysical Journal 83: 10. doi:10.1086/143696. Bibcode: 1936ApJ....83...10H.
- 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.
- Humason, Milton L. (1931). "Apparent Velocity-Shifts in the Spectra of Faint Nebulae". The Astrophysical Journal 74: 35. doi:10.1086/143287. Bibcode: 1931ApJ....74...35H.
- Hubble, Edwin; Humason, Milton L. (1931). "The Velocity-Distance Relation among Extra-Galactic Nebulae". The Astrophysical Journal 74: 43. doi:10.1086/143323. Bibcode: 1931ApJ....74...43H.
- 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.
- Humason, M. L. (1930). "The Rayton short-focus spectrographic objective". The Astrophysical Journal 71: 351. doi:10.1086/143255. Bibcode: 1930ApJ....71..351H.
- "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. doi:10.1086/123945. Bibcode: 1929PASP...41..244..
- 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
- Bailey, S. I. (1920). "Comet Skjellerup". Harvard College Observatory Bulletin 739: 1. Bibcode: 1920BHarO.739....1B.
- 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
- 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
- Liu, Michael C. (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. doi:10.1086/301399. Bibcode: 2000AJ....119.2556L.
- Fabian, A. C. (2001). "Chandra detection of the intracluster medium around 3C 294 at z = 1.786". Monthly Notices of the Royal Astronomical Society 322 (1): L11–L15. doi:10.1046/j.1365-8711.2001.04361.x. Bibcode: 2001MNRAS.322L..11F. Archived from the original on 2011-09-29. https://web.archive.org/web/20110929014203/http://www-xray.ast.cam.ac.uk/~jss/research/publications/mnr4361.pdf. (176 KB) ; 2001 January 25
- Dressler, A. (1993). "The Spectra and Morphology of Galaxies in High-Redshift Clusters". Observational Cosmology 51: 225. Bibcode: 1993ASPC...51..225D.
- European Space Agency ; Peering Far Back in Time to Uncover the Secrets of Galaxy Evolution ; 01 Dec 1992
- Dressler, Alan (1993). "Galaxies Far Away and Long Ago". Sky and Telescope 85 (4): 22. Bibcode: 1993S&T....85...22D.
- Dressler, Alan; Oemler, Augustus; Gunn, James E.; Butcher, Harvey (1993). "A Cluster of Nascent Galaxies at Z = 2?". The Astrophysical Journal 404: L45. doi:10.1086/186740. Bibcode: 1993ApJ...404L..45D.
- NED, Searching NED for object "3C 123"
- Spinrad, H. (1975). "3C 123: A distant first-ranked cluster galaxy at z = 0.637". The Astrophysical Journal 199: L3. doi:10.1086/181835. Bibcode: 1975ApJ...199L...3S.
- Naeye, Robert (13 January 2011). "The Most Distant Galaxy Cluster". http://www.skyandtelescope.com/news/113460379.html.
- BBC News, "Galaxy clusters' ancient light shows young cosmic city", Jason Palmer, 13 January 2011
- Associated Press, Oldest, most distant galaxy clusters found, 4:37 p.m. ET, Mon., Jan. 5, 2004
- 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.
- Science, Oldest Galaxy Cluster Found, 12 April 2002
- ESO Press Release 07/02 ; Most Distant Group of Galaxies Known in the Universe ; 9 April 2002
- 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
- ESO Press Release 03/02 ; UVES Investigates the Environment of a Very Remote Galaxy ; 11 March 2002
- Abell, George O. (1958). "The Distribution of Rich Clusters of Galaxies". The Astrophysical Journal Supplement Series 3: 211. doi:10.1086/190036. Bibcode: 1958ApJS....3..211A. https://thesis.library.caltech.edu/1581/1/Abell_GO_1957.pdf. Retrieved 2019-11-29. ; Abell's 1957 cluster list
Original source: https://en.wikipedia.org/wiki/ List of galaxy groups and clusters. Read more