2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/190010We present high-resolution rotation curves of a sample of 26 low surface brightness galaxies. From these curves we derive mass distributions using a variety of assumptions for the stellar mass-to-light ratio. We show that the predictions of current Cold Dark Matter models for the density profiles of dark matter halos are inconsistent with the observed curves. The latter indicate a core-dominated structure, rather than the theoretically preferred cuspy structure.Accepted for A&A, full version with high-res figures available at http://www.atnf.csiro.au/~edeblok/papers/bosma.ps.gzAstrophysicstext