Abstract: Extragalactic stars within galaxy clusters appear as the diffuse emission termed as the intracluster light (ICL). This stellar component has been suggested to be a promising tracer of the underlying dark matter (DM) distribution, but is often cumbersome to observe due to its low surface brightness. This is going to change with the upcoming data from novel telescopes like the Vera Rubin Observatory. In this talk, I will present results from a recent exploration by researchers at IA-UNAM and IRyA on the prospect of inferring the DM distribution of massive galaxy clusters from deep wide-field optical images. We carried this out using realistic mock observations of 40 massive clusters in the TNG300 cosmological, magneto-hydrodynamic simulation for the g′ band of the Wendelstein Wide-Field Imager. By comparing these images against DM maps, we find that the DM surface density profile of the central/main halo exhibits a tight, quasi-linear scaling relation with the combined surface brightness profile for the brightest cluster galaxy (BCG) and the intracluster light (ICL). This relation can be used to recover the DM concentration and mass within ≈ 23 and ≈ 15 per cent of their true values. Alternatively, we find that the central’s DM concentration can be estimated using the BCG+ICL fraction, the central’s DM mass using the BCG + ICL flux, and the total DM mass using the bolometric flux. These results serve as a proof-of-concept and demonstrate the feasibility of deriving DM characteristics of galaxy clusters to be observed with facilities like the Vera C. Rubin Observatory in the near future.
