The scatter, residual correlations and curvature of the <scp>sparc</scp> baryonic Tully–Fisher relation

Abstract

Abstract In recent work, Lelli et al. argue that the tightness of the baryonic Tully–Fisher relation (BTFR) of the sparc galaxy sample, and the weakness of the correlation of its residuals with effective radius, pose challenges to Λ cold dark matter cosmology. In this Letter, we calculate the statistical significance of these results in the framework of halo abundance matching, which imposes a canonical galaxy–halo connection. Taking full account of sample variance among sparc-like realizations of the parent halo population, we find the scatter in the predicted BTFR to be 3.6σ too high, but the correlation of its residuals with galaxy size to be naturally weak. Further, we find abundance matching to generate BTFR curvature in 3.0σ disagreement with the data, and a fraction of galaxies with non-flat rotation curves somewhat larger than observed.