Reconstruction of Galaxy Rotation Curves in Temporal Membrane Theory — Baryonic Upper-Bound Constraint and Common Scaling Across Three Distinct Galaxy Types —

Galaxy rotation curves are commonly interpreted as evidence for dark matter halos, particularly due to the persistence of high rotation velocities in the outer regions of galaxies.This work reexamines galaxy rotation curves from a different perspective, based on Temporal Membrane Theory (TMT), which focuses on the reconstruction of observational time rather than modifying spatial dynamics or gravitational laws. In TMT, the temporal membrane density ρt(r)\rho_t(r)ρt(r) is not introduced as a free fitting function to reproduce observed rotation curves.Instead, the observed rotation velocity is treated as an input quantity, and ρt(r)\rho_t(r)ρt(r) is reconstructed a posteriori as an effective descriptor of the temporal structure inferred from observations.Accordingly, the predictive content of the theory lies not in reproducing individual galaxies, but in the emergent properties of the reconstructed temporal membrane, such as its common functional form, systematic scaling with galaxy size, and stable scatter across galaxy populations. Applying the same theoretical structure and reconstruction conditions, this study analyzes three representative galaxies of distinct types (high surface brightness, low surface brightness, and dwarf galaxies).Without introducing distance rescaling, inclination correction, or halo-dependent tuning, the reconstruction remains stable across all cases. A key result is that, within Temporal Membrane Theory, the observed rotation velocity is always bounded above by the baryonic physical rotation velocity and asymptotically approaches it in the outer regions.This behavior arises naturally from the reconstruction of observational time and stands in structural contrast to standard ΛCDM models, where outer-region velocities exceed baryonic expectations due to dominant dark matter halos. This work does not aim to replace dark matter models, but rather demonstrates that galaxy rotation curves can be consistently reinterpreted within an alternative observational framework, highlighting a fundamentally different causal structure underlying similar phenomenological profiles.