Halo cluster shapes: insights from simulated galaxies and ICL with prospects for weak lensing applications

GONZALEZ, ELIZABETH J; MAKLER, MARTÍN; RAGONE-FIGUEROA, CINTHIA; GARCÍA LAMBAS, DIEGO; DONZELLI, CARLOS J; GRANATO, GIAN LUIGI

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2021 vol. 508 p. 1280 - 1295

0035-8711

We present a detailed study of the shapes and alignments of different galaxy cluster componentsusing hydrodynamical simulations. We compute shape parameters from the Dark Matter (DM)distribution, the galaxy members and the intra-cluster light (ICL). We assess how well the DMcluster shape can be constrained by means of the identified galaxy member positions and theICL. Further, we address the dilution factor introduced when estimating the cluster elongationusing weak-lensing stacking techniques, which arises due to the misalignment between the totalsurface mass distribution and the distribution of luminous tracers. The dilution is computedconsidering the alignment between the DM and the Brightest Cluster Galaxy, the galaxymembers and the ICL. Our study shows that distributions of galaxy members and ICL areless spherical than the DM component, although both are well aligned with the semi-majoraxis of the later. We find that the distribution of galaxy members hosted in more concentratedsubhalos is more elongated than the distribution of the DM. Moreover, these galaxies are betteraligned with the dark matter component compared to the distribution of galaxies hosted inless concentrated subhalos. We conclude that the positions of galaxy members can be used assuitable tracers to estimate the cluster surface density orientation, even when a low number ofmembers is considered. Our results provide useful information for interpreting the constraintson the shapes of galaxy clusters in observational studies.