Dipole repeller

A large underdense region of the nearby universe whose gravitational pull is weaker than average, contributing to the outward motion of surrounding galaxies and to the cosmic flow dipole.

Cosmic void: A vast region of the universe with substantially fewer galaxies and less matter than average. The Dipole Repeller is a particularly influential underdense region within the cosmic web.
Yehuda Hoffman: An Israeli cosmologist known for research on large-scale cosmic flows and the distribution of matter. Hoffman co-authored the analysis that identified the Dipole Repeller in reconstructed local flows.
Shapley Supercluster: A massive concentration of galaxies in the Centaurus constellation, among the largest structures in the nearby universe. Its gravitational attraction contributes to the flow pattern opposed by nearby underdense regions.
Dipole attractor: A dense cosmic region whose gravitational attraction contributes to the directional motion of nearby galaxies. It is the dense counterpart to the underdense region's apparent gravitational repulsion.
Gravitational attraction: The mutual attraction between masses described by gravity. Matter around the void attracts galaxies more strongly, making the underdense region appear to repel them.
Daniel Pomarède: A French astrophysicist who develops visualizations and analyses of large-scale cosmic structure. Pomarède co-authored the 2017 study that named and mapped the Dipole Repeller.
Great Attractor: A concentration of matter in the nearby universe associated with a strong gravitational pull on surrounding galaxies. It is a major attractor in the same reconstructed flow field as the Dipole Repeller.
Dark energy: The name for the component driving the accelerated expansion of the universe in the standard cosmological model. Dark energy accelerates cosmic expansion broadly; the repeller is a local effect of uneven matter density.
Peculiar velocity: An object's motion relative to the overall expansion of the universe. The repeller is inferred from peculiar velocities rather than from galaxies simply receding with expansion.
R. Brent Tully: An American astronomer known for mapping nearby galaxies and large-scale cosmic structure. Tully co-authored the work tracing local galaxy motions to attractors and repellers.

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Cosmic flowBroader topic: It illustrates how voids can shape flows by gravitationally pulling less strongly than surrounding regions.