Maps of the electron temperature obtained from the hydrogen recombination lines indicated in the top right corners of the panels, under the LTE approximation. The offsets are relative to the phase centre of the ALMA observations. The contours are the map of the 3 mm continuum emission shown in Fig. 1c, with contour levels ranging from 1.15 to 28.75 in steps of 4.6 mJy/beam. The synthesised beam is shown in the bottomright corner.