Top-Left: the spectrum. The double-peaked emission line is the Brγ line. Top-Middle: the squared visibilities as a function of spatial frequency, Top-Right: the closure phases as a function of spatial frequency, Bottom-Left: the differential visibilities (visibilities normalized to 1 in the continuum), Bottom-Middle: the closure phase, and Bottom-Right: the differential phase, the three former as a function of wavelength. In all plots, different colours represent different nights, and the black lines (resp. the black dots for the top panels) represent our best-fit model. “cycles/as”. or “cyc./as”. means “cycles per arc-seconds” or “arc-seconds-1”. For the closure phase plot, the spatial frequencies are the ones of the longest baseline. In the squared visibilities panel, one can see that the disc is clearly resolved at the largest baselines.