Structure of dark matter halos from hierarchical clustering. III. Shallowing of the inner cusp

We investigate the structure of the dark matter halo formed in the cold dark matter scenarios by N-body simulations with a parallel tree code on GRAPE cluster systems. We simulated eight halos with the mass of 4.4 x 10(14) to 1.6 x 10(15) M-circle dot in SCDM and LCDM models using up to 30 million particles. With the resolution of our simulations, the density profile is reliable down to 0.2% of the virial radius. Our results show that the slope of inner cusp within 1% virial radius is shallower than -1.5, and the radius where the shallowing starts exhibits run-to-run variation, which means that the innermost profile is not universal.