Local Sheet

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.[1] This region lies within a radius of about 7 Mpc, and galaxies beyond that distance show markedly different velocities.[2] 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 within the Local Sheet is only 40 km s−1 in the radial direction.[1]

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 185 km s−1 toward the cluster.[1] A second component is directed away from the center of the Local Void; an expanding region of space spanning an estimated 45 Mpc that is only sparsely populated with galaxies.[2] This component has a velocity of 259 km s−1.[1]

References

  1. ^ a b c d 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. Bibcode 2008ApJ...676..184T. doi:10.1086/527428. 
  2. ^ a b 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, Bibcode 2008IAUS..244..146T, doi:10.1017/S1743921307013932