Monday

In recent years it has become increasingly clear that the intracluster light (ICL) is an important component of the stellar mass budget at the centres of massive clusters. Despite this we lack detailed knowledge of the properties of the ICL and Without a detailed understanding of the composition and evolution of the ICL, in particular how it formed and the rate of growth are practically unconstrained and existing measurements are in tension with predictions. New facilities such as Euclid and LSST will allow ICL measurements at surface brightnesses fainter than 30 mag arcsec^-2 (in r) for the first time and facilitating self-consistent comparisons with the new generation high-resolution galaxy simulations such as EAGLE. Key questions include: (i) how rapid is the ICL assembly since z~1; (ii) does the ICL form from low-mass companions or Milky Way-type galaxies; (iii) how does ICL evolution depend on host cluster properties; (iv) what is the relation between ICL and brightest cluster galaxy morphology? The UK LSST Cluster Science team have proposed massive clusters in the range z=0.2-0.5 as science verification targets for LSST. In order to realise the potential of future facilities e.g. LSST and recover the ICL at low-surface brightness levels, it is vital to optimise the observing strategy and stacking techniques to reduce systematics caused by sky background, flat fielding, and PSF variation on large scales.