Bottom panel: HST F814W image (Hatch et al. 2008) in greyscale overlaid with the naturally weighted 246 GHz continuum map in green contours with levels of 1.5σ, 3σ, and 5σ. In the naturally weighted continuum map, we detect emission from companion #10 (and tentatively from #8) of Kuiper et al. (2011). The purple cross indicate the position of the nearby Ly α emitter at the position of the HzRG. The purple circles indicate the positions of Ly α emitters, the squares show the position of Hα and the triangles extremely red objects within the Ly α halo of MRC1138-262. The Ly α emitter #491 is offset by 0.̋8 from the companion source seen in the 246 GHz continuum emission west of the HzRG. Top panel: zoom in of the region around the companion sources. The purple circle shows the position of the Hα emitter #491 (Kurk et al. 2004b), which is close to the companion source seen in dust continuum emission.