This record presents an empirical re-analysis of the outer rotation-curve slopes in the SPARC galaxy sample. The analysis measures the logarithmic outer slope s = d log10 (Vₒbs) / d log10 (R) using ordinary least squares regression in log–log space. The study applies strict selection criteria (Q ≤ 2, R > 2. 5 Rdisk, Nₒuter ≥ 8), resulting in an accepted sample of 79 galaxies. The slope distribution shows a central tendency very close to zero (median −0. 000632), indicating that the characteristic outer dynamical state of disk galaxies is approximately flat, while still exhibiting significant dispersion. A strong negative correlation is found between the outer slope and the asymptotic rotation velocity (Pearson r = −0. 626; Spearman ρ = −0. 661), demonstrating that the outer slope is a scale-dependent dynamical parameter. Sensitivity tests using alternative outer-region definitions confirm that the ensemble average slope approaches zero as increasingly large galactocentric radii are considered. This work extends the empirical analysis presented in the previous record: DOI: 10. 5281/zenodo. 18904301 The results provide a quantitative characterization of the statistical structure of the outer rotation-curve slope distribution in the SPARC dataset.
Szabolcs Krehlik (Sun,) studied this question.