Local Sheet | |
---|---|
Observation data (Epoch ) | |
Brightest member | Local Group |
Major axis | 17 Mly (5 Mpc) |
Minor axis | 1.5 Mly (0.5 Mpc) |
Redshift | 0.00 |
Distance (co-moving) |
0 Mly (0 Mpc) |
See also: Galaxy groups, Galaxy clusters, List of superclusters | |
The Local Sheet in astronomy is a nearby region of the observable universe 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 km⋅s−1 with respect to the Local Sheet. Typical velocity dispersion of galaxies within the Local Sheet is only 66 in the radial direction. All nearby bright galaxies belong to the Local Sheet. The Local Sheet is part of the 40 km⋅s−1Local Volume and is in the Virgo Supercluster (Local Supercluster).
A significant component of the mean velocity of the galaxies in the Local Sheet comes as the result of the gravitational attraction of the Virgo Cluster of galaxies. This results in a peculiar motion of about toward the cluster. A second component is directed away from the center of the 185 km⋅s−1Local 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 . The Local Sheet is inclined 8° from the 259 km⋅s−1Local Supercluster (Virgo Supercluster).
The 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.