1610.04620
Einasto profiles and the dark matter power spectrum
Ludlow, Angulo
Study the mass accretion histories (MAHs) and density profiles of DM haloes using N-body sims of self-similar gravitational clustering from scale-free power spectra, P(k) ~ k^n. Pay particular attention to the density profiles curvature, which is characterized using the shape parameter, alpha, of an Einasto profile. In agreement with previous findings, the results suggest that, despite vast differences in their MAHs, the density profiles of virtualized haloes are remarkably alike. Nonetheless, clear departures from self-similarity are evident: for a given spectral index, alpha increases slightly but systematically with "peak height", nu==delta_SC/sigma(M,z), regardless of mass or redshift. More importantly, however, the "alpha-nu" relation depends on n: the steeper they initial power spectrum, the more gradual the curvature of both the mean MAHs and mean density profiles. These results are consistent with previous findings connecting the shapes of halo mass profiles and MAHs and imply that DM haloes are not structurally self-similar but, through the merger history, retain a memory of the linear density field from which they form.
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