Cosmology dependence of halo masses and concentrations in hydrodynamic simulations

Abstract

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 − 1 for critical over-densities $\Delta _\tt {vir}, \Delta _{200c}, \Delta _{500c}, \Delta _{2500c}$ and mean overdensity Δ200m. We provide the first mass-concentration (Mc) relation and sparsity relation (i.e. MΔ1 − MΔ2 mass conversion) of hydrodynamic simulations that is modelled by mass, redshift and cosmological parameters Ωm, Ωb, σ8, h0 as a tool for observational studies. We also quantify the impact that the Mc relation scatter and the assumption of NFW density profiles have on the uncertainty of the sparsity relation. We find that converting masses with the aid of a Mc relation carries an additional fractional scatter ($\approx 4\%$) 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.

The GOGREEN survey: Internal dynamics of clusters of galaxies at redshift 0.9–1.4

“…7). This is in line with theoretical expectations (Ragagnin et al 2021), according to which c 200 changes by <0.2 in the z and M 200 ranges of our four subsamples (see Table 2, Cols. 5 and 7); that is, the predicted changes are less than our observational uncertainties.…”

“…The agreement is particularly good with the most recent theoretical predictions, based on either DM-only or hydrodynamical simulations. We note that there is very little difference among the c 200 values predicted by DM-only (Child et al 2018) or by hydrodynamical simulations, indipendently of whether the latter account (Ragagnin et al 2021) or not (De Boni et al 2013) for feedback by an active galactic nucleus (AGN) in the central cluster region. The addition of baryonic effects to DM-only simulations can, in principle, lead to a substantial change in the halo c 200 (Fedeli 2012;Cui et al 2016).…”

“…Bottom panel: green horizontal line and shadings as in the top panel. Symbols with 1σ error bars are theoretical predictions from Bhattacharya et al (2013), Dutton & Macciò (2014), Correa et al (2015), Child et al (2018), De Boni et al (2013, Ragagnin et al (2021) for a halo of the same M 200 and z as our ensemble cluster, and rescaled to the cosmological parameters used in this paper. determinations of c 200 and the 8 clusters with X-ray data based determinations of c 200 , within the z and r 200 ranges of our sample.…”

“…6 we also show the theoretical predictions for c 200 of a halo with the same M 200 and z as our ensemble cluster, as obtained from numerical simulations. We consider, in particular, the theoretical predictions of De Boni et al (2013) and Ragagnin et al (2021), which are based on hydrodynamical simulations, and those of Bhattacharya et al (2013), Dutton & Macciò (2014), Correa et al (2015), Child et al (2018), which are based on gravity-only simulations. Since these simulations adopted different cosmological parameters, we use Eq.…”

“…Since these simulations adopted different cosmological parameters, we use Eq. ( 7) and Table 2 in Ragagnin et al (2021) to convert the theoretical c 200 values to those expected in the assumed cosmology in this paper. The value of σ 8 does not enter in our dynamical analysis; we assume σ 8 = 0.8.…”