Systematic Effects in the Inference of Inner Density Slopes in Galaxy Clusters

Analysis of dark and baryonic matter density profiles of galaxy clusters will lead to a better understanding of physical properties of DM haloes in the current lambda-CDM cosmological paradigm. Research has identified that the Navarro-Frenk-White (NFW) profiles obtained near-universally in numerical simulations overestimate DM density in inner regions of haloes, when compared against observations. In this research, we use IllustrisTNG to evaluate the behavior of inner density profiles when subjected to systematic effects associated with baryonic physics, cluster orientation, and stellar orbital anisotropy. We then investigate the potential sources of systematic bias associated with inferring the DM density profile from observations, by testing common assumptions made in estimating the profile from Jeans modelling. We perform qualitative and quantitative analyses to gauge the effect of these factors on the inner DM density distributions, ultimately concluding that these factors do not seem to adequately explain the simulation-observation disparity, possibly leading to questions about the validity of the lambda CDM cosmological paradigm.