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 to 80 megaparsecs (160 to 260 megalight-years)—with the largest found to date being the Hercules-Corona Borealis Great Wall at around 3 gigaparsecs (9.8 Gly) 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]
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)
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][23]
3 Gpc long,[10] 150 000 km/s deep[10] (in redshift space)
The largest known structure in the universe.[9][10][11] 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).[24][25]
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.[31] They are theorized to be protohyperclusters/proto-supercluster-complexes/galaxy filament precursors.[32]
^ abcdefHorvath 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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Fontanelli, P. (1983). "Clustering in the Universe: A filament of galaxies in the Coma/A1367 supercluster". Astronomy and Astrophysics. 138: 85–92. Bibcode:1984A&A...138...85F. ISSN0004-6361.
^Gavazzi, Giuseppe; Catinella, Barbara; Carrasco, Luis; et al. (May 1998). "The Star Formation Properties of Disk Galaxies: Hα Imaging of Galaxies in the Coma Supercluster". The Astronomical Journal. 115 (5): 1745–1777. arXiv:astro-ph/9801279. Bibcode:1998AJ....115.1745G. doi:10.1086/300314.
^ abcFairall, A. P.; Paverd, W. R.; Ashley, R. P. (1994). "Unveiling large-scale structures behind the Milky Way: Visualization of Nearby Large-Scale Structures". Astronomical Society of the Pacific Conference Series. 67: 21. Bibcode:1994ASPC...67...21F.
^Vanden Berk, Daniel E.; Stoughton, Chris; Crotts, Arlin P. S.; Tytler, David; Kirkman, David (2000). "QSO[CLC]s[/CLC] and Absorption-Line Systems surrounding the Hubble Deep Field". The Astronomical Journal. 119 (6): 2571–2582. arXiv:astro-ph/0003203. Bibcode:2000AJ....119.2571V. doi:10.1086/301404. S2CID117882449.