Galaxy filament

In physical cosmology, galaxy filaments (subtypes: supercluster complexes, galaxy walls, and galaxy sheets)[1][2] are the largest known structures in the universe. They are massive, thread-like formations, with a typical length of 50 to 80 megaparsecs h−1 (163 to 261 million light-years) that form the boundaries between large voids in the universe.[3] Filaments consist of gravitationally bound galaxies. Parts wherein many galaxies are very close to one another (in cosmic terms) are called superclusters.


In the standard model of the evolution of the universe, galactic filaments form along and follow web-like strings of dark matter.[4] It is thought that this dark matter dictates the structure of the Universe on the grandest of scales. Dark matter gravitationally attracts baryonic matter, and it is this "normal" matter that astronomers see forming long, thin walls of super-galactic clusters.


Discovery of structures larger than superclusters began in the late-1980s. In 1987, astronomer R. Brent Tully of the University of Hawaii's Institute of Astronomy identified what he called the Pisces–Cetus Supercluster Complex. In 1989, the CfA2 Great Wall was discovered,[5] followed by the Sloan Great Wall in 2003.[6] On January 11, 2013, researchers led by Roger Clowes of the University of Central Lancashire announced the discovery of a large quasar group, the Huge-LQG, which dwarfs previously discovered galaxy filaments in size.[7] In November 2013, using gamma-ray bursts as reference points, astronomers discovered the Hercules–Corona Borealis Great Wall, an extremely huge filament measuring more than 10 billion light-years across.[8][9][10]


Filament subtype of filaments have roughly similar major and minor axes in cross-section, along the lengthwise axis.

Filaments of Galaxies
Filament Date Mean distance Dimension Notes
Coma Filament The Coma Supercluster lies within the Coma Filament.[11] It forms part of the CfA2 Great Wall.[12]
Perseus–Pegasus Filament 1985 Connected to the Pisces–Cetus Supercluster, with the Perseus–Pisces Supercluster being a member of the filament.[13]
Ursa Major Filament Connected to the CfA Homunculus, a portion of the filament forms a portion of the "leg" of the Homunculus.[14]
Lynx–Ursa Major Filament (LUM Filament) 1999 from 2000 km/s to 8000 km/s in redshift space Connected to and separate from the Lynx–Ursa Major Supercluster.[14]
z=2.38 filament around protocluster ClG J2143-4423 2004 z=2.38 110Mpc A filament the length of the Great Wall was discovered in 2004. As of 2008, it was still the largest structure beyond redshift 2.[15][16][17][18]
  • A short filament, detected by identifying an alignment of star-forming galaxies, in the neighborhood of the Milky Way and the Local Group was proposed by Adi Zitrin and Noah Brosch.[19] The reality of this filament, and the identification of a similar but shorter filament, were the result of a study by McQuinn et al. (2014) based on distance measurements using the TRGB method.[20]

Galaxy walls

The galaxy wall subtype of filaments have a significantly greater major axis than minor axis in cross-section, along the lengthwise axis.

Walls of Galaxies
Wall Date Mean distance Dimension Notes
CfA2 Great Wall (Coma Wall, Great Wall, Northern Great Wall, Great Northern Wall, CfA Great Wall) 1989 z=0.03058 251Mpc long
750 Mly long
250 Mly wide
20 Mly thick
This was the first super-large large-scale structure or pseudo-structure in the universe to be discovered. The CfA Homunculus lies at the heart of the Great Wall, and the Coma Supercluster forms most of the homunculus structure. The Coma Cluster lies at the core.[21][22]
Sloan Great Wall (SDSS Great Wall) 2003 z=0.07804 433Mpc long This was the largest known galaxy filament to be discovered,[21] until it was eclipsed by the Hercules–Corona Borealis Great Wall found ten years later.
Sculptor Wall (Southern Great Wall, Great Southern Wall, Southern Wall) 8000 km/s long
5000 km/s wide
1000 km/s deep
(in redshift space dimensions)
The Sculptor Wall is "parallel" to the Fornax Wall and "perpendicular" to the Grus Wall.[23][24]
Grus Wall The Grus Wall is "perpendicular" to the Fornax and Sculptor Walls.[24]
Fornax Wall The Fornax Cluster is part of this wall. The wall is "parallel" to the Sculptor Wall and "perpendicular" to the Grus Wall.[23][24]
Hercules–Corona Borealis Great Wall 2013 z≈2[9] 3 Gpc long,[9]
150 000 km/s deep[9]
(in redshift space)
The largest known structure in the universe.[8][9][10] This is also the first time since 1991 that a galaxy filament/great wall held the record as the largest known structure in the universe.
Large-scale structure of light distribution in the universe
Galaxy filaments, walls and voids form web-like structures.
  • A "Centaurus Great Wall" (or "Fornax Great Wall" or "Virgo Great Wall") has been proposed, which would include the Fornax Wall as a portion of it (visually created by the Zone of Avoidance) along with the Centaurus Supercluster and the Virgo Supercluster also known as our Local Supercluster within which the Milky Way galaxy is located (implying this to be the Local Great Wall).[23][24]
  • A wall was proposed to be the physical embodiment of the Great Attractor, with the Norma Cluster as part of it. It is sometimes referred to as the Great Attractor Wall or Norma Wall.[25] This suggestion was superseded by the proposal of a supercluster, Laniakea, that would encompass the Great Attractor, Virgo Supercluster, Hydra-Centaurus Superclusters.[26]
  • A wall was proposed in 2000 to lie at z=1.47 in the vicinity of radio galaxy B3 0003+387.[27]
  • A wall was proposed in 2000 to lie at z=0.559 in the northern Hubble Deep Field (HDF North).[28][29]

Map of nearest galaxy walls

The Universe within 500 million light years, showing the nearest galaxy walls

Large Quasar Groups

Large quasar groups (LQGs) are some of the largest structures known.[30] They are theorized to be protohyperclusters/proto-supercluster-complexes/galaxy filament precursors.[31]

Large Quasar Groups
LQG Date Mean distance Dimension Notes
Clowes–Campusano LQG
(U1.28, CCLQG)
1991 z=1.28
  • longest dimension: 630 Mpc
It was the largest known structure in the universe from 1991 to 2011, until U1.11's discovery.
U1.11 2011 z=1.11
  • longest dimension: 780 Mpc
Was the largest known structure in the universe for a few months, until Huge-LQG's discovery.
Huge-LQG 2012 z=1.27
  • characteristic size: 500 Mpc
  • longest dimension: 1240 Mpc
It was the largest structure known in the universe,[30][31] until the discovery of the Hercules–Corona Borealis Great Wall found one year later.[9]

Supercluster complex

Supercluster complex
Name Date Mean distance Dimension Notes
Pisces–Cetus Supercluster Complex 1987 1 billion ly wide,
150 million ly deep
Contains Virgo Supercluster and Local Group

Maps of large-scale distribution

Superclusters atlasoftheuniverse

The universe within 1 billion light-years (307 Mpc) of Earth, showing local superclusters forming filaments and voids


Map of nearest walls, voids and superclusters


2dF survey map, containing the SDSS Great Wall

2MASS LSS chart-NEW Nasa

2MASS XSC infrared sky map

See also


  1. ^ Boris V. Komberg, Andrey V. Kravtsov, Vladimir N. Lukash; "The search and investigation of the Large Groups of Quasars" arXiv:astro-ph/9602090;;
  2. ^ R.G. Clowes; "Large Quasar Groups - A Short Review"; The New Era of Wide Field Astronomy, ASP Conference Series, Vol. 232.; 2001; Astronomical Society of the Pacific; ISBN 1-58381-065-X ; Bibcode2001ASPC..232..108C
  3. ^ Bharadwaj, Somnath; Bhavsar, Suketu; Sheth, Jatush V (2004). "The Size of the Longest Filaments in the Universe" (PDF). Astrophys J. 606 (1): 25–31. arXiv:astro-ph/0311342. Bibcode:2004ApJ...606...25B. doi:10.1086/382140.
  4. ^ Riordan, Michael; David N. Schramm (March 1991). Shadows of Creation: Dark Matter and the Structure of the Universe. W H Freeman & Co (Sd). ISBN 0-7167-2157-0.
  5. ^ M. J. Geller & J. P. Huchra, Science 246, 897 (1989).
  6. ^ Sky and Telescope, "Refining the Cosmic Recipe", 14 November 2003
  7. ^ Wall, Mike (2013-01-11). "Largest structure in universe discovered". Fox News.
  8. ^ a b Horvath, Istvan; Hakkila, Jon; Bagoly, Zsolt (2014). "Possible structure in the GRB sky distribution at redshift two". Astronomy & Astrophysics. 561: id.L12. arXiv:1401.0533. Bibcode:2014A&A...561L..12H. doi:10.1051/0004-6361/201323020.
  9. ^ a b c d e f Horvath I., Hakkila J., and Bagoly Z.; Hakkila, J.; Bagoly, Z. (2013). "The largest structure of the Universe, defined by Gamma-Ray Bursts". 7th Huntsville Gamma-Ray Burst Symposium, GRB 2013: paper 33 in eConf Proceedings C1304143. 1311: 1104. arXiv:1311.1104. Bibcode:2013arXiv1311.1104H.CS1 maint: Multiple names: authors list (link)
  10. ^ a b Klotz, Irene (2013-11-19). "Universe's Largest Structure is a Cosmic Conundrum". discovery. Retrieved 2013-11-22.
  11. ^ 'Astronomy and Astrophysics' (ISSN 0004-6361), vol. 138, no. 1, Sept. 1984, pp. 85-92. Research supported by Cornell University "The Coma/A 1367 filament of galaxies" 09/1984 Bibcode1984A&A...138...85F
  13. ^ 'Astrophysical Journal', Part 1 (ISSN 0004-637X), vol. 299, Dec. 1, 1985, p. 5-14. "A possible 300 megaparsec filament of clusters of galaxies in Perseus-Pegasus" 12/1985 Bibcode1985ApJ...299....5B
  14. ^ a b The Astrophysical Journal Supplement Series, Volume 121, Issue 2, pp. 445-472. "Photometric Properties of Kiso Ultraviolet-Excess Galaxies in the Lynx-Ursa Major Region" 04/1999 Bibcode1999ApJS..121..445T
  16. ^ "The Distribution of Lyα‐Emitting Galaxies at z = 2.38". The Astrophysical Journal. 602: 545–554. arXiv:astro-ph/0311279. Bibcode:2004ApJ...602..545P. doi:10.1086/381145.
  17. ^ "The Distribution of Lyα‐emitting Galaxies at z =2.38. II. Spectroscopy". The Astrophysical Journal. 614: 75–83. arXiv:astro-ph/0406413. Bibcode:2004ApJ...614...75F. doi:10.1086/423417.
  18. ^ Relativistic Astrophysics Legacy and Cosmology - Einstein's, ESO Astrophysics Symposia, Volume . ISBN 978-3-540-74712-3. Springer-Verlag Berlin Heidelberg, 2008, p. 358 "Ultraviolet-Bright, High-Redshift ULIRGS" 00/2008 Bibcode2008ralc.conf..358W
  19. ^ Zitrin, A.; Brosch, N. (2008). "The NGC 672 and 784 galaxy groups: evidence for galaxy formation and growth along a nearby dark matter filament". Monthly Notices of the Royal Astronomical Society. 390: 408–420. arXiv:0808.1789. Bibcode:2008MNRAS.390..408Z. doi:10.1111/j.1365-2966.2008.13786.x.
  20. ^ McQuinn, K.B.W.; et al. (2014). "Distance Determinations to SHIELD Galaxies from Hubble Space Telescope Imaging". The Astrophysical Journal. 785: 3. arXiv:1402.3723. Bibcode:2014ApJ...785....3M. doi:10.1088/0004-637x/785/1/3.
  21. ^ a b Chin. J. Astron. Astrophys. Vol. 6 (2006), No. 1, 35–42 "Super-Large-Scale Structures in the Sloan Digital Sky Survey" (PDF).
  22. ^ Scientific American, Vol. 280, No. 6, p. 30 - 37 ""Mapping the Universe"" (PDF). Archived from the original (PDF) on 2008-07-04. (1.43 MB) 06/1999 Bibcode1999SciAm.280f..30L
  23. ^ a b c Unveiling large-scale structures behind the Milky Way. Astronomical Society of the Pacific Conference Series, Vol. 67; Proceedings of a workshop at the Observatoire de Paris-Meudon; 18–21 January 1994; San Francisco: Astronomical Society of the Pacific (ASP); c1994; edited by Chantal Balkowski and R. C. Kraan-Korteweg, p.21 ; Visualization of Nearby Large-Scale Structures ; Fairall, A. P., Paverd, W. R., & Ashley, R. P. ; 1994ASPC...67...21F
  24. ^ a b c d Astrophysics and Space Science, Volume 230, Issue 1-2, pp. 225-235 "Large-Scale Structures in the Distribution of Galaxies" 08/1995 Bibcode1995Ap&SS.230..225F
  25. ^ World Science, Wall of galaxies tugs on ours, astronomers find April 19, 2006
  26. ^ Tully, R. Brent; Courtois, Hélène; Hoffman, Yehuda; Pomarède, Daniel (2 September 2014). "The Laniakea supercluster of galaxies". Nature (published 4 September 2014). 513 (7516): 71–73. arXiv:1409.0880. Bibcode:2014Natur.513...71T. doi:10.1038/nature13674. PMID 25186900.
  27. ^ The Astronomical Journal, Volume 120, Issue 5, pp. 2331-2337. "B3 0003+387: AGN-Marked Large-Scale Structure at Redshift 1.47?" 11/2000 Bibcode2000AJ....120.2331T doi:10.1086/316827
  28. ^ FermiLab, "Astronomers Find Wall of Galaxies Traversing the Hubble Deep Field", DARPA, Monday, January 24, 2000
  29. ^ "QSO[CLC]s[/CLC] and Absorption-Line Systems surrounding the Hubble Deep Field". The Astronomical Journal. 119: 2571–2582. arXiv:astro-ph/0003203. Bibcode:2000AJ....119.2571V. doi:10.1086/301404.
  30. ^ a b ScienceDaily, "Biggest Structure in Universe: Large Quasar Group Is 4 Billion Light Years Across", Royal Astronomical Society, 11 January 2013 (accessed 13 January 2013)
  31. ^ a b Clowes, Roger G.; Harris, Kathryn A.; Raghunathan, Srinivasan; Campusano, Luis E.; Soechting, Ilona K.; Graham, Matthew J.; "A structure in the early universe at z ~ 1.3 that exceeds the homogeneity scale of the R-W concordance cosmology"; arXiv:1211.6256 ; Bibcode2012arXiv1211.6256C ; doi:10.1093/mnras/sts497 ; Monthly Notices of the Royal Astronomical Society, 11 January 2013

Further reading

External links

CfA2 Great Wall

The Great Wall (also called Coma Wall), sometimes specifically referred to as the CfA2 Great Wall, is an immense galaxy filament. It is one of the largest known superstructures in the observable universe.

This structure was discovered c. 1989 by a team of American astronomers led by Margaret J. Geller and John Huchra while analyzing data gathered by the second CfA Redshift Survey of the Harvard-Smithsonian Center for Astrophysics (CfA).

Coma Filament

Coma Filament is a galaxy filament. The filament contains the Coma Supercluster of galaxies and forms a part of the CfA2 Great Wall.

Cygnus (constellation)

Cygnus is a northern constellation lying on the plane of the Milky Way, deriving its name from the Latinized Greek word for swan. Cygnus is one of the most recognizable constellations of the northern summer and autumn, and it features a prominent asterism known as the Northern Cross (in contrast to the Southern Cross). Cygnus was among the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations.

Cygnus contains Deneb (ذنب, translit. ḏanab, tail) -which is one of the brightest stars in the night sky and is the most distant first-magnitude star- as its "tail star" and one corner of the Summer Triangle. It also has some notable X-ray sources and the giant stellar association of Cygnus OB2. Cygnus is also known as the Northern Cross. One of the stars of this association, NML Cygni, is one of the largest stars currently known. The constellation is also home to Cygnus X-1, a distant X-ray binary containing a supergiant and unseen massive companion that was the first object widely held to be a black hole. Many star systems in Cygnus have known planets as a result of the Kepler Mission observing one patch of the sky, an area around Cygnus. In addition, most of the eastern part of Cygnus is dominated by the Hercules–Corona Borealis Great Wall, a giant galaxy filament that is the largest known structure in the observable universe, covering most of the northern sky.

Fornax Wall

The Fornax Wall is a superstructure known as a galaxy filament or galaxy wall. It is a long filament of galaxies with a major axis longer than its minor one. The filament contains not only Dorado Group but also the Fornax cluster of galaxies, which lies at the same distance. It is "parallel" to the Sculptor Wall and "perpendicular" to the Grus Wall.

Graphical timeline of the Big Bang

This timeline of the Big Bang shows a sequence of events as currently theorized by scientists.

It is a logarithmic scale that shows second instead of second. For example, one microsecond is . To convert −30 read on the scale to second calculate second = one millisecond. On a logarithmic time scale a step lasts ten times longer than the previous step.

Hadron epoch

In physical cosmology, the hadron epoch was the period in the evolution of the early universe during which the mass of the universe was dominated by hadrons. It started approximately 10−6 seconds after the Big Bang, when the temperature of the universe had fallen sufficiently to allow the quarks from the preceding quark epoch to bind together into hadrons. Initially the temperature was high enough to allow the formation of hadron/anti-hadron pairs, which kept matter and anti-matter in thermal equilibrium. However, as the temperature of the universe continued to fall, hadron/anti-hadron pairs were no longer produced. Most of the hadrons and anti-hadrons were then eliminated in annihilation reactions, leaving a small residue of hadrons. The elimination of anti-hadrons was completed by one second after the Big Bang, when the following lepton epoch began.

Lynx–Ursa Major Filament

Lynx–Ursa Major Filament (LUM Filament) is a galaxy filament.The filament is connected to and separate from the Lynx–Ursa Major Supercluster.

NGC 5965

NGC 5965 is a spiral galaxy located in the constellation Draco. It is located at a distance of circa 150 million light years from Earth, which, given its apparent dimensions, means that NGC 5965 is about 260,000 light years across. It was discovered by William Herschel οn May 5, 1788. Two supernovae have been observed in NGC 5965, SN 2001 cm (type II, mag 17.5) and SN 2018cyg (type II, mag 17.0).NGC 5965 is seen nearly edge-on, with an inclination of 80 degrees. Dust is seen across the galactic disk, while there is also a red dust lane at the nucleus. The bulge is X-shaped, that suggests that the galaxy is actually barred. NGC 5965 along with another edge-on galaxy, NGC 5746, were the galaxies used to confirm that peanut shaped bulge are associated with the presence of a bar, by spectographically observing the disturbance caused at the velocity distributions of the galaxies.

The galaxy features some level of disk disturbance, like a warp, as the outer part of the disk along with a ring-like dust lane appear to be on a different plane from the bulge, but it could also be a projection effect. When observed in K band, the galaxy features a stellar ring.NGC 5965 lies in a galaxy filament which also includes NGC 5987 and its loose group, which includes NGC 5981, NGC 5982, NGC 5985, three galaxies known as the Sampler.

Perseus–Pegasus Filament

Perseus–Pegasus Filament is a galaxy filament containing the Perseus-Pisces Supercluster and stretching for roughly a billion light years (or over 300/h Mpc). Currently, it is considered to be one of the largest known structures in the universe. This filament is adjacent to the Pisces–Cetus Supercluster Complex.

Photon epoch

In physical cosmology, the photon epoch was the period in the evolution of the early universe in which photons dominated the energy of the universe. The photon epoch started after most leptons and anti-leptons were annihilated at the end of the lepton epoch, about 10 seconds after the Big Bang. Atomic nuclei were created in the process of nucleosynthesis which occurred during the first few minutes of the photon epoch. For the remainder of the photon epoch, the universe contained a hot dense plasma of nuclei, electrons and photons. 370,000 years after the Big Bang the temperature of the universe fell to the point where nuclei could combine with electrons to create neutral atoms. As a result, photons no longer interacted frequently with matter, the universe became transparent and the cosmic microwave background radiation was created and then structure formation took place.

Pisces–Cetus Supercluster Complex

The Pisces–Cetus Supercluster Complex is a galaxy filament. It includes the Virgo Supercluster which in turn contains the Local Group, the galaxy cluster that includes the Milky Way.

This filament is adjacent to the Perseus–Pegasus Filament.

However, a 2014 study indicates that the Virgo Supercluster is only a lobe of a greater supercluster, Laniakea.

Quark epoch

In physical cosmology the Quark epoch was the period in the evolution of the early universe when the fundamental interactions of gravitation, electromagnetism, the strong interaction and the weak interaction had taken their present forms, but the temperature of the universe was still too high to allow quarks to bind together to form hadrons. The quark epoch began approximately 10−12 seconds after the Big Bang, when the preceding electroweak epoch ended as the electroweak interaction separated into the weak interaction and electromagnetism. During the quark epoch the universe was filled with a dense, hot quark–gluon plasma, containing quarks, leptons and their antiparticles. Collisions between particles were too energetic to allow quarks to combine into mesons or baryons. The quark epoch ended when the universe was about 10−6 seconds old, when the average energy of particle interactions had fallen below the binding energy of hadrons. The following period, when quarks became confined within hadrons, is known as the hadron epoch.

Saraswati Supercluster

The Saraswati Supercluster is a massive galaxy supercluster about 1.2 gigaparsecs (4,000 million light years) away within the Stripe 82 region of SDSS, in the direction of the constellation Pisces. It is one of the largest structures found in the universe, with a major axis in diameter of about 200 Mpc (652 million light years). It consists of at least 43 galaxy clusters, and has the mass of 2 × 1016 M☉, forming a galaxy filament.

Sloan Great Wall

The Sloan Great Wall (SGW) is a cosmic structure formed by a giant wall of galaxies (a galaxy filament). Its discovery was announced from Princeton University on October 20, 2003, by J. Richard Gott III, Mario Jurić, and their colleagues, based on data from the Sloan Digital Sky Survey.

Somnath Bharadwaj

Somnath Bharadwaj (born 28 October 1964) is an Indian theoretical physicist who works on Theoretical Astrophysics and Cosmology.

Bharadwaj was born in India, studied at the Indian Institute of Technology in Kharagpur, and later received his Ph.D. from the Indian Institute of Science. After having worked at the Harish-Chandra Research Institute, he is now a professor at IIT Kharagpur. He has made significant contributions to the dynamics of large-scale structure formation.

In 2003, he was selected to be one of the professors from IIT whose class room lectures would be broadcast in the Eklavya Technology Channel.Bharadwaj was an invited speakers on Galaxy Formation at the prestigious Indo-US Frontier of Science symposium which was organized by the U.S. National Academy of Sciences in 2005.He is currently in the Editorial Board of the Journal of Astrophysics & Astronomy published by the Indian Academy of Sciences.


A supercluster is a large group of smaller galaxy clusters or galaxy groups; it is among the largest-known structures of the cosmos. The Milky Way is part of the Local Group galaxy group (which contains more than 54 galaxies), which in turn is part of the Laniakea Supercluster. This supercluster spans over 500 million light-years, while the Local Group spans over 10 million light-years. The number of superclusters in the observable universe is estimated to be 10 million.

Ursa Major Filament

Ursa Major Filament is a galaxy filament. The filament is connected to the CfA Homunculus, a portion of the filament forms a portion of the "leg" of the Homunculus.

Virgo Supercluster

The Virgo Supercluster (Virgo SC) or the Local Supercluster (LSC or LS) is a mass concentration of galaxies containing the Virgo Cluster and Local Group, which in turn contains the Milky Way and Andromeda galaxies. At least 100 galaxy groups and clusters are located within its diameter of 33 megaparsecs (110 million light-years). The Virgo SC is one of about 10 million superclusters in the observable universe and is in the Pisces–Cetus Supercluster Complex, a galaxy filament.

A 2014 study indicates that the Virgo Supercluster is only a lobe of an even greater supercluster, Laniakea, a larger, competing referent of Local Supercluster centered on the Great Attractor.

Active nuclei
Energetic galaxies
Low activity
See also

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