Fitting functions for a disk-galaxy model with different ACDM-halo profiles (Research Note) (original) (raw)

Aims. We present an adaptation of the standard scenario of disk-galaxy formation to the concordant ΛCDM cosmology aimed to derive analytical expressions for the scale length and rotation speed of present-day disks that form within four different, cosmologically motivated protogalactic dark matter halo-density profiles. Methods. We invoke a standard galaxy-formation model that includes virial equilibrium of spherical dark halos, specific angular momentum conservation during gas cooling, and adiabatic halo response to the gas inflow. The mean mass-fraction and mass-to-light ratio of the central stellar disk are treated as free parameters whose values are tuned to match the zero points of the observed sizeluminosity and circular speed-luminosity relations of galaxies. Results. We supply analytical formulas for the characteristic size and rotation speed of disks built inside Einasto r 1/6 , Hernquist, Burkert, and Navarro-Frenk-White dark matter halos. These expressions match simultaneo...