SIMBAD references

Observational determinations of the correlation between the characteristic density δ_c and the virial mass M_vir of dark halos constitute a critical test for models of hierarchical structure formation. Using the dynamical properties of dark halos reconstructed from the galaxy distributions in massive systems (groups/clusters) and the rotation curves in less massive systems (dwarf, low surface brightness and spiral galaxies) drawn from the literature, we confirm the existence of the δ_c-M_vir relation over a broad mass range from 10¹⁰M_☉ to 10¹⁵M_☉, which is in gross consistency with the prediction of a flat cosmological model with Ω_M=0.3 and Ω_Λ=0.7. It is pointed out that previous analyses based on the measurements of X-ray emitting gas and the hydrostatic equilibrium hypothesis, which claimed a shallower scale-free spectrum of n≃-1 for initial density fluctuations, may suffer from nongravitational heating influence especially in low-mass systems.