Maps of the extended (top) and compact (bottom) components that contribute to the core [C ii] 158 μm emission of SDSS J1148+5251 within v ∈ ( − 200,200) km s^-1. The map of the extended component has been obtained by subtracting from the uv data the point source model fit. The map of the compact component has been produced by applying a uv tapering that cuts the visibilities with uv radius <80 m; this operation increases the spatial resolution of the data (the resulting beam size is 1.1′′×1.1′′). Negative and positive contours are in steps of 2σ for the extended component in the top panel (1σ rms noise of 0.10 Jy beam^-1 km s^-1). For the compact component in the bottom panel, contours correspond to − 3σ, 3σ, 5σ to 30σ in steps of 5σ (1σ rms noise of 0.11 Jy beam^-1 km s^-1). In both panels, the cross indicates the pointing and phase centre, corresponding to the optical position of the quasar.