Cosmology dependence of halo masses and concentrations in hydrodynamic simulations

We employ a set of Magneticum cosmological hydrodynamic simulations that span over 15 different cosmologies, and extract masses and concentrations of all well-resolved haloes between z = 0 and 1 for critical overdensities Delta(vir), Delta(200c), Delta(500c), Delta(2500c) and mean overdensity Delta(200m). We provide the first mass-concentration (Mc) relation and sparsity relation (i.e. M-Delta 1 - M-Delta 2 mass conversion) of hydrodynamic simulations that is modelled by mass, redshift, and cosmological parameters Omega(m), Omega(b), sigma(8), h(0) as a tool for observational studies. We also quantify the impact that the Mc relation scatter and the assumption of Navarro-Frank-White (NFW) density profiles have on the uncertainty of the sparsity relation. We find that converting masses with the aid of an Mc relation carries an additional fractional scatter (approximate to 4 per cent) originated from deviations from the assumed NFW density profile. For this reason, we provide a direct mass-mass conversion relation fit that depends on redshift and cosmological parameters. We release the package HYDRO MC, a PYTHON tool that perform all kind of conversions presented in this paper.

Automated summary

The study extracts masses and concentrations of haloes at different critical overdensities from cosmological hydrodynamic simulations, and provides a mass-concentration relation as well as a conversion tool. It finds an additional fractional scatter in mass conversions and offers a mass-mass conversion relation based on redshift and cosmological parameters.