SZE Observables, Pressure Profiles and Center Offsets in Magneticum Simulation Galaxy Clusters

Abstract

We present a detailed study of the galaxy cluster thermal \ac{sze} signal $Y$ and pressure profiles using {\it Magneticum} Pathfinder hydrodynamical simulations. With a sample of 50,000 galaxy clusters ($M_{500c}>1.4\times 10^{14}{\mathrm{M}}_{\odot }$) out to $z=2$, we find significant variations in the shape of the pressure profile with mass and redshift and present a new generalized NFW model that follows these trends. We show that the thermal pressure at $R_{500c}$ accounts for only 80~percent of the pressure required to maintain hydrostatic equilibrium, and therefore even idealized hydrostatic mass estimates would be biased at the 20~percent level. We compare the cluster \ac{sze} signal extracted from a sphere with different virial-like radii, a virial cylinder within a narrow redshift slice and the full light cone, confirming small scatter ($\ddot{I}{ƒ}_{\ln Y}\simeq 0.087$) in the sphere and showing that structure immediately surrounding clusters increases the scatter and strengthens non self-similar redshift evolution in the cylinder. Uncorrelated large scale structure along the line of sight leads to an increase in the \ac{sze} signal and scatter that is more pronounced for low mass clusters, resulting in non self-similar trends in both mass and redshift and a mass dependent scatter that is $\sim 0.16$ at low masses. The scatter distribution is consistent with log-normal in all cases. We present a model of the offsets between the center of the gravitational potential and the \ac{sze} center that follows the variations with cluster mass and redshift.

20 pages, 15 figures, submitted to MNRAS