Emergent Finite-Response Dynamics in SPARC Rotation Curves: A Dark-Matter-Free ECSM Test Across 175 Disk Galaxies

This work presents a dark-matter-free rotation-curve test of the Emergent Condensate Superfluid Medium (ECSM) framework using the SPARC database of 175 nearby disk galaxies. Instead of fitting galaxies with particle dark-matter halos, the model treats the observed baryonic radial profile as the source of a finite-response medium state. In this interpretation, the inner galaxy defines a coherent response domain, the domain boundary marks a transition in relaxation behaviour, and the outer disk samples a delayed or stretched medium response. The resulting effective circular-speed profile is compared with observed SPARC rotation curves, with baryon-only and MOND-like reference models used as baselines. In the current full-sample implementation, the ECSM response model improves on the baryon-only baseline for approximately 93–96% of galaxies, improves on the raw MOND-like reference for approximately 80–81% of galaxies, and gives a lower global log-acceleration error than the tested baryon-only, deep-MOND, and simple MOND interpolation references. A targeted failure-class analysis shows that the worst-fitting galaxies do not consistently prefer either a universal outer-memory suppression term or a simple gradient-derived activation rule. Instead, their residuals form a structured abnormal class, consistent with non-circular motions, bulge–disk decomposition tension, inclination or distance uncertainty, disturbed gas, or non-equilibrium outer-domain structure. The paper does not claim empirical lensing validation. Instead, it identifies lensing as a derived propagation-gradient prediction of ECSM to be tested separately against galaxy-galaxy lensing data. The results support the view that MOND-like galactic phenomenology can arise from finite-response medium dynamics without introducing particle dark matter halos at the level of individual rotation-curve modelling.