Continuum-subtracted, velocity-integrated [Cii] emission (natural weighting) overplotted on a HST CANDELS YJH image (Grogin et al. 2011; Koekemoer et al. 2011). The HST emission traced by is dominated by an unresolved point source, consistent with AGN-dominated rest-frame UV-optical emission, with no clear host galaxy visible. Both the [Cii], which is spatially resolved in our ALMA observations at ~0.̋6 resolution, and the spatially-unresolved continuum emission (see Fig. 3) peak on the position of the optical/near-infrared source within 0.̋2, indicating that the AGN lies close to the centre of the FIR emission. The contour levels are −3, 3, 5, 10, 15, 20, 25, and 30σ, where σ = 7.5 mJy km s^-1.