09-17-2021-0159 - Giant Void

The Giant Void (also known as the Giant Void in NGH, Canes Venatici Supervoid, and AR-Lp 36) is an extremely large region of space with an underdensity of galaxies and located in the constellation Canes Venatici. It is the second-largest-confirmed void to date, with an estimated diameter of 300 to 400 Mpc (1 to 1.3 billion light-years)^[1] and is approximately 1.5 billion light-years away (z = 0.116).^[1] It was discovered in 1988,^[2] and was the largest void in the Northern Galactic Hemisphere,^[1] and possibly the second-largest ever detected. Even the hypothesized "Eridanus Supervoid" corresponding to the location of the WMAP cold spot is dwarfed by this void, although the Giant Void does not correspond to any significant cooling to the cosmic microwave background.

Although a vast void, inside it are 17 galaxy clusters, concentrated in a spherical shaped region 50 Mpc in diameter.^[1] Studies of the motion of the clusters show that they have no interaction to each other, meaning the density of the clusters is very low resulting in weak gravitational interaction.^[1] The void's location in the sky is close to the Boötes void.

Artist's conception of the Giant Void and the filaments and walls that surround it. The internal clusters can also be appreciated. (Credit: Pablo Carlos Budassi).

 https://en.wikipedia.org/wiki/Giant_Void

https://en.wikipedia.org/wiki/Great_Attractor

https://en.wikipedia.org/wiki/Sloan_Great_Wall

https://en.wikipedia.org/wiki/Category:Galaxy_filaments

https://en.wikipedia.org/wiki/Category:Local_Sheet

The Local Sheet in astronomy is a nearby extragalactic region of space where the Milky Way, the members of the Local Group and other galaxies share a similar peculiar velocity.^[2] This region lies within a radius of about 7 Mpc (23 Mly),^[3] 0.46 Mpc (1.5 Mly) thick,^[1] and galaxies beyond that distance show markedly different velocities.^[3] The Local Group has only a relatively small peculiar velocity of 66 km⋅s⁻¹with respect to the Local Sheet. Typical velocity dispersion of galaxies is only 40 km⋅s⁻¹ in the radial direction.^[2] Nearly all nearby bright galaxies belong to the Local Sheet.^[1] The Local Sheet is part of the Local Volume and is in the Virgo Supercluster (Local Supercluster).^[4] The Local Sheet forms a wall of galaxies delineating one boundary of the Local Void.^[5]

https://en.wikipedia.org/wiki/Local_Sheet

The Local Void is a vast, empty region of space, lying adjacent to the Local Group.^[3][4] Discovered by Brent Tully and Rick Fisher in 1987,^[5] the Local Void is now known to be composed of three separate sectors, separated by bridges of "wispy filaments".^[4] The precise extent of the void is unknown, but it is at least 45 Mpc(150 million light-years) across,^[6] and possibly 150 to 300 Mpc.^[7][8] The Local Void appears to have significantly fewer galaxies than expected from standard cosmology.^[9]

https://en.wikipedia.org/wiki/Local_Void

The Local Group is the galaxy group that includes the Milky Way. It has a total diameter of roughly 3 megaparsecs (10 million light-years; 9×10²² metres), and a total mass of the order of 2×10¹² solar masses (4×10⁴² kg).^[1] It consists of two collections of galaxies in a "dumbbell" shape: the Milky Way and its satellites form one lobe, and the Andromeda Galaxy and its satellites constitute the other. The two collections are separated by about 800 kpc (3×10⁶ ly; 2×10²² m) and are moving toward one another with a velocity of 123 km/s.^[2] The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies.

https://en.wikipedia.org/wiki/Local_Group

https://en.wikipedia.org/wiki/Boötes_I_(dwarf_galaxy)

https://en.wikipedia.org/wiki/Leo_A

https://en.wikipedia.org/wiki/Pisces_II_(dwarf_galaxy)

https://en.wikipedia.org/wiki/Draco_Dwarf

https://en.wikipedia.org/wiki/Virgo_Stellar_Stream

https://en.wikipedia.org/wiki/Wolf–Lundmark–Melotte

https://en.wikipedia.org/wiki/Hercules_(dwarf_galaxy)

https://en.wikipedia.org/wiki/Triangulum_Galaxy

https://en.wikipedia.org/wiki/Category:Local_Group

https://en.wikipedia.org/wiki/Category:Lyman-alpha_blobs

https://en.wikipedia.org/wiki/Category:Voids_(astronomy)

https://en.wikipedia.org/wiki/Category:Large-scale_structure_of_the_cosmos

https://en.wikipedia.org/wiki/Category:Dark_matter