Structural Rigidity of the Radial Acceleration Relation Revealed by Offset-Controlled Analysis

This work presents an offset-controlled residual analysis of the Radial Acceleration Relation (RAR) using the highest-quality (Q=1) subset of the SPARC database. By subtracting per-galaxy median residuals, we separate galaxy-level normalization modes from acceleration-dependent structural deviations. The analysis shows that a substantial fraction of the apparent scatter behaves as a rigid normalization offset rather than deformation of the functional form. After normalization control, residual curvature is strongly suppressed and different interpolation functions become statistically indistinguishable within current precision. The results reinforce the structural rigidity of the RAR and provide empirical constraints relevant to both modified gravity and ΛCDM baryon–halo coupling interpretations.