Cluster Merger Lensing from Weyl and Ricci Curvature Co-evolution
We propose that the gravitational lensing–gas offsets observed in merging galaxy clusters follow from the independent evolution of the Ricci and Weyl components of spacetime curvature, a structural feature of general relativity. The Weyl tensor (the free gravitational field) is collisionless by construction and separates from collisional gas during a cluster merger. The predicted offset d = v × t, with one geometric variable (viewing angle) per system, reproduces four well-studied mergers: the Bullet Cluster, El Gordo, the Musket Ball Cluster, and Abell 520. The anomalous "dark core" in Abell 520, where the lensing peak coincides with the gas rather than separating from it, is explained as a near line-of-sight geometry (θ ≈ 8°), independently confirmed by spectroscopic dynamical analysis. Four observational tests are proposed. A simplified numerical simulation demonstrates that initial Weyl curvature is retained through gravitational collapse, and the Raychaudhuri equation is shown to reduce the damping in the Weyl evolution equations as structures form. Whether accumulated Weyl curvature is quantitatively sufficient to account for the observed lensing masses remains an open question requiring a full numerical solution of the 1+3 covariant evolution equations.
Authors
- Scott Weller
Publication Details
- Journal
- Zenodo (CERN European Organization for Nuclear Research)
- Published
- 2026-05-18
- DOI
- https://doi.org/10.5281/zenodo.20276055
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- preprint