Galaxy filament explained

In cosmology, galaxy filaments are the largest known structures in the universe, consisting of walls of galactic superclusters. These massive, thread-like formations can commonly reach 50/h to 80/h Megaparsecs (50to)—with the largest found to date being the Hercules-Corona Borealis Great Wall at around 3Gpc in length—and form the boundaries between voids.^[1] Due to the accelerating expansion of the universe, the individual clusters of gravitationally bound galaxies that make up galaxy filaments are moving away from each other at an accelerated rate; in the far future they will dissolve.^[2]

Galaxy filaments form the cosmic web and define the overall structure of the observable universe.^{[3] [4] [5]}

Discovery

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. The CfA2 Great Wall was discovered in 1989,^[6] followed by the Sloan Great Wall in 2003.^[7]

In January 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.^[8] In November 2013, using gamma-ray bursts as reference points, astronomers discovered the Hercules–Corona Borealis Great Wall, an extremely large filament measuring more than 10 billion light-years across.^{[9] [10] [11]}

Filaments

The 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
				The Coma Supercluster lies within the Coma Filament.^[12] It forms part of the CfA2 Great Wall.^[13]
	1985			Connected to the Pisces–Cetus Supercluster, with the Perseus–Pisces Supercluster being a member of the filament.^[14]
				Connected to the CfA Homunculus, a portion of the filament forms a portion of the "leg" of the Homunculus.
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.^[15]
z=2.38 filament around protocluster ClG J2143-4423	2004	z=2.38	110 Mpc	A filament the length of the Great Wall was discovered in 2004. As of 2008, it was still the largest structure beyond redshift 2.^[16] ^[17] ^[18] ^[19]

• A short filament was proposed by Adi Zitrin and Noah Brosch—detected by identifying an alignment of star-forming galaxies—in the neighborhood of the Milky Way and the Local Group.^[20] The proposal of this filament, and 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.^[21]

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	251 Mpc 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.^[22]
Sloan Great Wall (SDSS Great Wall)	2003	z=0.07804	433 Mpc long	This was the largest known galaxy filament to be discovered,^[23] 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.^[24]
Grus Wall				The Grus Wall is "perpendicular" to the Fornax and Sculptor Walls.^[25]
				The Fornax Cluster is part of this wall. The wall is "parallel" to the Sculptor Wall and "perpendicular" to the Grus Wall.
Hercules–Corona Borealis Great Wall	2013	z≈2	3 Gpc long, 150 000 km/s deep (in redshift space)	The largest known structure in the universe. 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.

• 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 the Local Supercluster, within which the Milky Way galaxy is located (implying this to be the Local Great Wall).
• 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.^[26] This suggestion was superseded by the proposal of a supercluster, Laniakea, that would encompass the Great Attractor, Virgo Supercluster, Hydra–Centaurus Superclusters.^[27]
• A wall was proposed in 2000 to lie at z=1.47 in the vicinity of radio galaxy B3 0003+387.^[28]
• A wall was proposed in 2000 to lie at z=0.559 in the northern Hubble Deep Field (HDF North).^{[29] [30]}

Map of nearest galaxy walls

Large Quasar Groups

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

Large Quasar Groups

LQG	Date	Mean distance	Dimension	Notes
Clowes–Campusano LQG (U1.28, CCLQG)	1991	z=1.28		It was the largest known structure in the universe from 1991 to 2011, until U1.11's discovery.
U1.11	2011	z=1.11		Was the largest known structure in the universe for a few months, until Huge-LQG's discovery.
Huge-LQG	2012	z=1.27		It was the largest structure known in the universe,^[31] ^[32] until the discovery of the Hercules–Corona Borealis Great Wall found one year later.

Supercluster complex

Pisces–Cetus Supercluster Complex

See also

• List of largest cosmic structures
• Galaxy
• Galaxy cluster
• Galaxy supercluster
• Illustris project
• Large-scale structure
• List of galaxies
• List of galaxy groups and clusters
• Void (astronomy)
• Infrared cirrus

Further reading

• Kevin A. Pimbblet, Web site: Pulling Out Threads from the Cosmic Tapestry: Defining Filaments of Galaxies ., arXiv, 14 March 2005.

External links

• Pictures of the filamentary network
• The Universe Within One Billion Light Years with List of Nearby Superclusters (from the Atlas of the Universe):

Notes and References

1. Bharadwaj . Somnath . Somnath Bharadwaj . Bhavsar . Suketu . Sheth . Jatush V . 2004 . The Size of the Longest Filaments in the Universe . Astrophys J . 606 . 1. 25–31 . 10.1086/382140. astro-ph/0311342 . 2004ApJ...606...25B . 10473973 .
2. Web site: Siegel . Ethan . Our Home Supercluster, Laniakea, Is Dissolving Before Our Eyes . 2023-11-13 . Forbes . en.
3. Web site: Cosmic Web . 2023-06-06 . NASA Universe Exploration . en . 2023-03-27 . https://web.archive.org/web/20230327065720/https://universe.nasa.gov/resources/89/cosmic-web/ . live .
4. Boris V. Komberg, Andrey V. Kravtsov, Vladimir N. Lukash; "The search and investigation of the Large Groups of Quasars" ; ;
5. 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; ;
6. M. J. Geller & J. P. Huchra, Science 246, 897 (1989). . Science . 17 November 1989 . 246 . 4932 . 897–903 . 10.1126/science.246.4932.897 . 2009-09-18 . https://web.archive.org/web/20080621082540/http://www.sciencemag.org/cgi/content/abstract/246/4932/897 . 2008-06-21 . live . Huchra . John P. . Geller . Margaret J. . 17812575 . 31328798 .
7. Sky and Telescope, "Refining the Cosmic Recipe", 14 November 2003
8. Web site: Wall . Mike . Largest structure in universe discovered . 2013-01-11 . Fox News . 2013-01-12 . https://web.archive.org/web/20130112015836/http://www.foxnews.com/science/2013/01/11/largest-structure-in-universe-discovered/ . 2013-01-12 . live .
9. 1401.0533 . 2014A&A...561L..12H . Possible structure in the GRB sky distribution at redshift two . Horvath . Istvan . Hakkila . Jon . Bagoly . Zsolt . Astronomy & Astrophysics . 2014 . 561 . id.L12 . 10.1051/0004-6361/201323020 . 24224684 .
10. Horvath I., Hakkila J., and Bagoly Z. . 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. 2013. 1311.1104. 2013arXiv1311.1104H. Hakkila. J.. Bagoly. Z..
11. Web site: Klotz . Irene . Universe's Largest Structure is a Cosmic Conundrum . 2013-11-19 . discovery . 2013-11-22 . https://web.archive.org/web/20131130010953/http://www.space.com/23754-universe-largest-structure-cosmic-conundrum.html . 2013-11-30 . live .
12. 'Astronomy and Astrophysics', vol. 138, no. 1, Sept. 1984, pp. 85–92. Research supported by Cornell University "The Coma/A 1367 filament of galaxies" 09/1984
13. THE ASTRONOMICAL JOURNAL, 115:1745-1777, 1998 May; THE STAR FORMATION PROPERTIES OF DISK GALAXIES: Hα IMAGING OF GALAXIES IN THE COMA SUPERCLUSTER
14. 'Astrophysical Journal', Part 1, vol. 299, Dec. 1, 1985, pp. 5–14. "A possible 300 megaparsec filament of clusters of galaxies in Perseus-Pegasus" 12/1985
15. 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
16. NASA, GIANT GALAXY STRING DEFIES MODELS OF HOW UNIVERSE EVOLVED, January 7, 2004
17. 10.1086/381145 . 2004ApJ...602..545P . 602 . 2 . The Distribution of Lyα-Emitting Galaxies at z = 2.38 . The Astrophysical Journal . 545–554. astro-ph/0311279 . Palunas . Povilas . Teplitz . Harry I. . Francis . Paul J. . Williger . Gerard M. . Woodgate . Bruce E. . 2004 . 990891 .
18. 10.1086/423417 . 2004ApJ...614...75F . 614 . 1 . The Distribution of Lyα-emitting Galaxies at z =2.38. II. Spectroscopy . The Astrophysical Journal . 75–83. astro-ph/0406413 . 2004 . Francis . Paul J. . Palunas . Povilas . Teplitz . Harry I. . Williger . Gerard M. . Woodgate . Bruce E. . 118037575 .
19. Relativistic Astrophysics Legacy and Cosmology - Einstein's, ESO Astrophysics Symposia, Volume . . Springer-Verlag Berlin Heidelberg, 2008, p. 358 "Ultraviolet-Bright, High-Redshift ULIRGS" 00/2008
20. 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 . 1. 408–420 . 10.1111/j.1365-2966.2008.13786.x . free . 2008MNRAS.390..408Z. 0808.1789 . 16296617 .
21. McQuinn . K.B.W. . etal . 2014 . Distance Determinations to SHIELD Galaxies from Hubble Space Telescope Imaging . The Astrophysical Journal . 785 . 1. 3 . 10.1088/0004-637x/785/1/3 . 2014ApJ...785....3M. 1402.3723 . 118465292 .
22. Scientific American, vol. 280, no. 6, pp. 30–37 Web site: Mapping the Universe . dead . https://web.archive.org/web/20080704115259/http://cosmos.phy.tufts.edu/%7Ezirbel/ast21/sciam/MappingUniverse.pdf . 2008-07-04 .   06/1999
23. Chin. J. Astron. Astrophys. Vol. 6 (2006), No. 1, 35–42 Web site: Super-Large-Scale Structures in the Sloan Digital Sky Survey . 2008-08-02 . 2013-06-10 . https://web.archive.org/web/20130610110617/http://www.iop.org/EJ/article/1009-9271/6/1/004/chjaa_6_1_004.pdf . live .
24. 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, California: 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.; 1994 ASPC...67...21F
25. Astrophysics and Space Science, volume 230, issue 1–2, pp. 225–235 "Large-Scale Structures in the Distribution of Galaxies" 08/1995
26. World Science, Wall of galaxies tugs on ours, astronomers find April 19, 2006
27. The Laniakea supercluster of galaxies . 2 September 2014 . 4 September 2014 . Nature . 513 . 7516 . 71–73 . 2014Natur.513...71T . 1409.0880 . 10.1038/nature13674 . Tully . R. Brent . Courtois . Hélène . Hoffman . Yehuda . Pomarède . Daniel . 25186900. 205240232 .
28. The Astronomical Journal, volume 120, issue 5, pp. 2331–2337. "B3 0003+387: AGN-Marked Large-Scale Structure at Redshift 1.47?" 11/2000
29. FermiLab, "Astronomers Find Wall of Galaxies Traversing the Hubble Deep Field", DARPA, Monday, January 24, 2000
30. 10.1086/301404 . 2000AJ....119.2571V . 119 . 6 . QSO[CLC]s[/CLC] and Absorption-Line Systems surrounding the Hubble Deep Field . The Astronomical Journal . 2571–2582. astro-ph/0003203 . 2000 . Vanden Berk . Daniel E. . Stoughton . Chris . Crotts . Arlin P. S. . Tytler . David . Kirkman . David . 117882449 .
31. Web site: Biggest structure in universe: Large quasar group is 4 billion light years across . 2023-09-16 . ScienceDaily . en.
32. 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"; ; ; ; Monthly Notices of the Royal Astronomical Society, 11 January 2013