Abstract
A stationary surface response is formulated for an isolated, settled disk galaxy as a possible endpoint of deformation memory. The response is described by a scalar field coupled to the projected baryonic density, with a positive quadratic Hamiltonian and a finite range Green function constructed from the modified Bessel function K 0 . SPARC selects the long range regime, where the additional circular support follows the enclosed projected mass. Its normalization is fixed by the baryonic Tully–Fisher relation through a single acceleration scale. For 153 primary SPARC galaxies, the model gives a median relative rotation curve residual of 0.166, compared with 0.159 for the radial acceleration relation and 0.081 for NFW fits with two parameters for each galaxy. The inferred acceleration scale agrees with the canonical galactic value. Bootstrap resampling places the response and radial acceleration relation within the same population interval. Their predictions separate through their dependences on baryonic concentration, source mass, surface brightness, and gas fraction. These relations provide observational tests of an enclosed mass response as a description of galactic dynamics.