Formation and Evolution of
Galaxy Clusters Across Cosmic Time

The intracluster light (ICL) around galaxy groups and clusters is an excellent probe to understand the growth of the brightest cluster galaxies (BCG) and the host systems. Studying the ICL around galaxy groups is particularly interesting for the abundance of groups and the complementary halo mass range galaxy groups cover compared to the more massive clusters. However, there are a number of challenges to analyze the ICL around groups. One major challenge is the unambiguous detection of the group center of potential based on photometry. Another is the physical interpretation of the stacked ICL profile due to any possible dependency of the ICL fraction on the host group or the BCG properties. We explore these two challenges using the Hydrangea cosmological hydrodynamic simulation suite. We prepare mock observations for the 511 galaxy groups and clusters in Hydrangea that match our observational KiDS+GAMA galaxy group sample, and test the effect of misidentifying the group center and the dependence of ICL on the BCG properties. We find that about 20 % of the spectroscopically selected galaxy groups are likely to have a misidentified center, out of which, about 10 % are likely due to the projection effect. This possible miscentering does not significantly affect the mass density profile, or the surface brightness profile of the ensemble for our target sample. However, it may be of importance for more sensitive data from next-generation surveys. We also show that the ICL fraction is strongly correlated with the group BCG luminosity, the group halo mass, and the group richness. Therefore, while stacking the groups to improve the signal-to-noise ratio, a sub-stacking based on their BCG luminosity will make the physical interpretation of the ICL more straightforward.