Our Peculiar Motion Away from the Local Void

Abstract

The peculiar velocity of the Local Group of galaxies manifested in the Cosmic\nMicrowave Background dipole is found to decompose into three dominant\ncomponents. The three components are clearly separated because they arise on\ndistinct spatial scales and are fortuitously almost orthogonal in their\ninfluences. The nearest, which is distinguished by a velocity discontinuity at\n~7 Mpc, arises from the evacuation of the Local Void. We lie in the Local Sheet\nthat bounds the void. Random motions within the Local Sheet are small. Our\nGalaxy participates in the bulk motion of the Local Sheet away from the Local\nVoid. The component of our motion on an intermediate scale is attributed to the\nVirgo Cluster and its surroundings, 17 Mpc away. The third and largest\ncomponent is an attraction on scales larger than 3000 km/s and centered near\nthe direction of the Centaurus Cluster. The amplitudes of the three components\nare 259, 185, and 455 km/s, respectively, adding collectively to 631 km/s in\nthe reference frame of the Local Sheet. Taking the nearby influences into\naccount causes the residual attributed to large scales to align with observed\nconcentrations of distant galaxies and reduces somewhat the amplitude of motion\nattributed to their pull. On small scales, in addition to the motion of our\nLocal Sheet away from the Local Void, the nearest adjacent filament, the Leo\nSpur, is seen to be moving in a direction that will lead to convergence with\nour filament. Finally, a good distance to an isolated galaxy within the Local\nVoid reveals that this dwarf system has a motion of at least 230 km/s away from\nthe void center. Given the velocities expected from gravitational instability\ntheory in the standard cosmological paradigm, the distance to the center of the\nLocal Void must be at least 23 Mpc from our position. The Local Void is large!\n