The Radial Profile of RAR Residuals in SPARC Galaxies: Systematic Overprediction Inside r/r_d < 0.8

The radial acceleration relation (RAR) of disk galaxies has been reported to show no significant correlation between residuals and galactocentric radius (Lelli et al. 2017). However, previous analyses examined residuals against absolute radius R rather than radius normalized by the disk scale length r_d. Here we stack RAR residuals from 163 SPARC galaxies (3,271 data points) as a function of r/r_d. Using per-galaxy averaging to account for within-galaxy correlations, we find that the RAR systematically overpredicts observed accelerations in the inner disk: the per-galaxy mean residual at r/r_d 0.5. The peak deviation at r/r_d ~ 0.3–0.5 overlaps with the radial address where NFW dark matter cusps produce…