| Abstract: | Understanding the distribution of dark-matter halos in galaxies is crucial for testing ΛCDM (or alternative theories of gravity). In this talk I will present a phenomenological pattern, found in the rotational data of disk galaxies, which may point to an underlying property of dark-halo distributions. The pattern is revealed by re-expressing rotation curves in terms of angular velocities. We find that in a large sample of 143 high-quality rotation curves, the difference between observed and baryon-predicted angular velocities is well-described by a constant shift. This constant angular-velocity offset provides a surprisingly effective fit, outperforming traditional dark-halo models. Incorporating this constant-offset feature into the dynamical equations yields a single-parameter dark-halo profile explicitly and intrinsically linked to the baryonic distribution. This result suggests a deeper coupling between baryonic and dark matter components. |