Characterising Strong Lensing Galaxy Clusters using the Millennium-XXL and MOKA simulations

TL;DR

This study analyzes strong lensing galaxy clusters using Millennium-XXL and MOKA simulations, revealing the distribution of Einstein radii, the effects of substructures, and implications for cosmological parameters.

Contribution

It provides a detailed comparison of simulated and predicted Einstein radius distributions, incorporating substructures, triaxiality, and baryonic effects, and explores their cosmological implications.

Findings

Einstein radius distribution follows a log-normal shape.

Projection effects significantly boost the largest Einstein radii.

Distribution sensitive to cosmological parameters {}_M and {}_8.

Abstract

In this paper we investigate the strong lensing statistics in galaxy clusters. We extract dark matter haloes from the Millennium-XXL simulation, compute their Einstein radius distribution, and find a very good agreement with Monte Carlo predictions produced with the MOKA code. The distribution of the Einstein radii is well described by a log-normal distribution, with a considerable fraction of the largest systems boosted by different projection effects. We discuss the importance of substructures and triaxiality in shaping the size of the critical lines for cluster size haloes. We then model and interpret the different deviations, accounting for the presence of a Bright Central Galaxy (BCG) and two different stellar mass density profiles. We present scaling relations between weak lensing quantities and the size of the Einstein radii. Finally we discuss how sensible is the distribution of the Einstein radii on the cosmological parameters {\Omega}_M-{\sigma}_8 finding that cosmologies with higher {\Omega}_M and {\sigma}_8 possess a large sample of strong lensing clusters. The Einstein radius distribution may help distinguish Planck13 and WMAP7 cosmology at 3{\sigma}.