ALMA Band 6 dust continuum emission from SPT2349-56, showing the core region (top left) and the north extension (top right) 45″ away. The pointing centre and instrument FWHM of APEX SEPIA345 (orange) and SEPIA660 (cyan) observations are overlaid. The Band 6 synthesised beam (magenta) is shown in the bottom-left of each panel. The black contours indicate ALMA Band 10 dust continuum detections towards the core region at signal-to-noise ratio levels of 3, 6, 10, and 15. Several continuum sources are labelled, as identified by Hill et al. (2020). Bottom left: The [C II] (orange; δV = 110 km s⁻¹) and [O III] 88 μm (cyan; δV = 140 km s⁻¹) spectra (Flux density vs. velocity, corrected using z = 4.304). Bottom right: The [C II] spectra (flux density or antenna temperature vs. frequency) shown for both observations of the core (orange; δV = 100 km s⁻¹) and north (fuchsia; δV = 100 km s⁻¹) fields.