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« The Dekel+ profile: a mass-dependent dark-matter density profile with flexible inner slope and analytic potential, velocity dispersion, and lensing properties »

Jonathan Freundlich
Racah Inst. Physics, Hebrew Univ. (Jerusalem, Israël)

Using the NIHAO suite of cosmological zoom-in simulations, we explore a parametric function for the dark-matter halo density profile subject to baryonic effects. This profile has variable inner slope and concentration parameter, and it allows analytic expressions for the gravitational potential, velocity dispersion, and lensing properties. We show that this profile provides better fits to simulated profiles than the Einasto profile and the generalized NFW profile with variable inner slope, in particular towards the halo centers, and that its parameters are correlated with the stellar-to-halo mass ratio Mstar/Mhalo. This defines a mass-dependent density profile describing the dark matter profiles in all galaxies, which can be directly applied to observed rotation curves of galaxies, gravitational lenses, and semi-analytic models of galaxy formation and satellite-galaxy evolution. The effect of baryons manifests itself in the profile parameters by a sharp drop of the inner density slope and a 20% decrease of the concentration parameter for log(Mstar/Mhalo) between -3.5 and -2, which corresponds to Mstar between 10^7 and 10^10 Msun. The accuracy by which this profile fits simulated galaxies is similar to certain multi-parameter, mass-dependent profiles, but its fewer parameters and analytic nature make it most desirable for many purposes.

mardi 28 avril 2020 - 10:30
Webinaire, Institut d'Astrophysique
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