Galaxy filament


In physical cosmology, galaxy filaments Boris V. Komberg, Andrey V. Kravtsov, Vladimir N. Lukash; "The search and investigation of the Large Groups of Quasars" ; ; 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 that form the boundaries between large voids in the universe. Filaments consist of gravitationally bound galaxies. Parts wherein many galaxies are very close to one another are called superclusters.

Formation

In the standard model of the evolution of the universe, galactic filaments form along and follow web-like strings of dark matter. 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

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, followed by the Sloan Great Wall in 2003. 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. 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.

Filaments

Filament subtype of filaments have roughly similar major and minor axes in cross-section, along the lengthwise axis.
FilamentDateMean distanceDimensionNotes
Coma FilamentThe Coma Supercluster lies within the Coma Filament. It forms part of the CfA2 Great Wall.
Perseus–Pegasus Filament1985Connected to the Pisces–Cetus Supercluster, with the Perseus–Pisces Supercluster being a member of the filament.
Ursa Major FilamentConnected to the CfA Homunculus, a portion of the filament forms a portion of the "leg" of the Homunculus.
Lynx–Ursa Major Filament 1999from 2000 km/s to 8000 km/s in redshift spaceConnected to and separate from the Lynx–Ursa Major Supercluster.
z=2.38 filament around protocluster ClG J2143-44232004z=2.38110MpcA filament the length of the Great Wall was discovered in 2004. As of 2008, it was still the largest structure beyond redshift 2.

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

WallDateMean distanceDimensionNotes
CfA2 Great Wall 1989z=0.03058251Mpc long

Large Quasar Groups

s are some of the largest structures known. They are theorized to be protohyperclusters/proto-supercluster-complexes/galaxy filament precursors.
LQGDateMean distanceDimensionNotes
Clowes–Campusano LQG
1991z=1.28
It was the largest known structure in the universe from 1991 to 2011, until U1.11's discovery.
U1.112011z=1.11
  		• Was the largest known structure in the universe for a few months, until Huge-LQG's discovery.
    Huge-LQG2012z=1.27
  		• It was the largest structure known in the universe, 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 until the discovery of the Hercules–Corona Borealis Great Wall found one year later.

    Supercluster complex

    Maps of large-scale distribution



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