Recent astronomical observations have revealed a surprising diversity in galaxy mass distributions. Some galaxies appear to contain little or no dark matter, while others remain strongly dominated by it. This tension poses a significant challenge to standard models of galaxy formation and to our understanding of gravity on galactic scales. In this study, we test Relativistic Coherent Vacuum Gravity Theory (rCVGT) against a representative sample of galaxies spanning both extremes: systems with very low inferred dark matter content and systems where dark matter appears to dominate. We find that a purely local vacuum response, coupled only to visible matter, is insufficient to explain the full range of observations. To address this, we introduce a minimal extension that incorporates a non-local contribution linked to the structure of the vacuum coherence field. This modification allows the theory to consistently reproduce the observed mass distributions across all galaxy types considered. Our results indicate that gravity on galaxy scales may depend not only on local matter, but also on extended and non-local vacuum effects. This provides a unified framework capable of explaining both dark matter-deficient and dark matter-dominated galaxies without requiring particle dark matter.
Steen Møller Nielsen (Wed,) studied this question.