|Observation data (Epoch )|
|Brightest member||Local Group|
|Major axis||17 Mly (5 Mpc) |
|Minor axis||1.5 Mly (0.5 Mpc) |
|0 Mly (0 Mpc)|
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. This region lies within a radius of about 7 Mpc (23 Mly), 0.46 Mpc (1.5 Mly) thick, and galaxies beyond that distance show markedly different velocities. The Local Group has only a relatively small peculiar velocity of 66 km⋅s−1 with respect to the Local Sheet. Typical velocity dispersion of galaxies is only 40 km⋅s−1 in the radial direction. Nearly all nearby bright galaxies belong to the Local Sheet. The Local Sheet is part of the Local Volume and is in the Virgo Supercluster (Local Supercluster). The Local Sheet forms a wall of galaxies delineating one boundary of the Local Void.
A significant component of the mean velocity of the galaxies in the Local Sheet appears as the result of the gravitational attraction of the Virgo Cluster of galaxies, resulting in a peculiar motion ~185 km⋅s−1 toward the cluster. A second component is directed away from the center of the Local Void; an expanding region of space spanning an estimated 45 Mpc (150 Mly) that is only sparsely populated with galaxies. This component has a velocity of 259 km⋅s−1. The Local Sheet is inclined 8° from the Local Supercluster (Virgo Supercluster).
The so-called Council of Giants is a ring of twelve large galaxies surrounding the Local Group in the Local Sheet, with a radius of 3.75 Mpc (12.2 Mly). Ten of these are spirals, while the remaining two are ellipticals. The two ellipticals (Maffei 1 and Centaurus A) lie on opposite sides of the Local Group, and their formation may have prompted the development of the Local Group. The Local Sheet's own development outlines a concentration of dark matter in a filament.
|Catalog ID||Name||Constellation||Distance (Mly)||Mass *|
|NGC 253||Sculptor Galaxy||Sculptor||11||10.805|
|PGC 9892||Maffei 1||Cassiopeia||11||10.928|
|PGC 10217||Maffei 2||Cassiopeia||11||10.493|
|NGC 3031||M 81||Ursa Major||12||10.905|
|NGC 3034||M 82||Ursa Major||11||10.573|
|NGC 4736||M 94||Canes Venatici||15||10.458|
|NGC 4826||M 64||Coma Berenices||16||10.496|
|NGC 5236||M 83||Hydra||16||10.642|
|NGC 5128||Centaurus A||Centaurus||11||11.169|
|ESO 97-G13||Circinus Galaxy||Circinus||14||10.559|
* The mass is given as the logarithm of the mass in solar masses.
- Local Void, the Local Sheet defining the wall of galaxies at one end of the void
- Leo Chain, a nearby cluster of galaxies opposite to the Local Void from the Local Sheet
- Supergalactic coordinate system, the coordinate system taking the Local Sheet, the Supergalactic Plane, as its X–Y bases
- "Milky Way amidst a 'Council of Giants'". Science Daily. 11 March 2014.
- Tully, R. Brent; Shaya, Edward J.; Karachentsev, Igor D.; Courtois, Hélène M.; Kocevski, Dale D.; Rizzi, Luca; Peel, Alan (March 2008). "Our Peculiar Motion Away from the Local Void". The Astrophysical Journal. 676 (1): 184–205. arXiv:0705.4139. Bibcode:2008ApJ...676..184T. doi:10.1086/527428.
- Tully, R. Brent (May 2008), "The Local Void is Really Empty", Dark Galaxies and Lost Baryons, Proceedings of the International Astronomical Union, IAU Symposium, 244, pp. 146–151, arXiv:0708.0864, Bibcode:2008IAUS..244..146T, doi:10.1017/S1743921307013932
- McCall, Marshall L. (29 April 2013). "A Council of Giants". Monthly Notices of the Royal Astronomical Society (published 10 March 2014). 440 (1): 405–426. arXiv:1403.3667. Bibcode:2014MNRAS.440..405M. doi:10.1093/mnras/stu199.
- Shaya, Ed J.; Tully, R. Brent; (December 2013). "The Formation of the Local Group Planes of Galaxies". Monthly Notices of the Royal Astronomical Society. Oxford University Press. Royal Astronomical Society. 436 (3): 2096–2119. arXiv:1307.4297. Bibcode:2013MNRAS.436.2096S. doi:10.1093/mnras/stt1714.CS1 maint: Uses authors parameter (link)