Morphological properties of the galaxies in the field of the overdensity. Left, H band (F160W) NICMOS image of the cluster, in logarithmic greyscale. The image is a composite of frames taken with the NIC3 camera during 7 HST orbits, reduced using the NICRED pipeline and combined with Multidrizzle. Galaxies with Y − K_s > 2 are shown in red and galaxies with Y − K_s < 2 in blue. Sérsic indices of the best-fit model are indicated on top of each galaxy, except for those that are too point-like, which are labelled “compact”. Right, morphologies of four representative galaxies from the H band image. For each galaxy we show, from left to right, the observed image, the best-fit Sérsic model and the residuals image after subtraction of the model, all in the same logarithmic grey scale.