Chandra contours in the [0.5–2] keV band, overlaid on a g − r − 3.6   μm image of the cluster. The contours result from the filtering of Fig. 1 by a wavelet adapted to low-count statistics (Starck & Pierre 1998): the image is de-noised but intensity is not strictly conserved. The first contour is indicative of the background level. The two green circles indicate the X-ray sources for which a spectroscopic redshift is available, in addition to source A (see Table 1). The red circles highlight the B sources. The yellow-dashed circle has a radius of 1 Mpc at the cluster redshift. The yellow cross indicates the center of the IRAC overdensity (Papovich et al. 2010).