Channel maps from the fitting process of the MATISSE data using PMOIRED across the wavelength interval of 4.050–4.056 μm (Brα emission). Each panel corresponds to a single sampled wavelength slice; the associated Doppler velocity with respect to the local standard of rest, v_LSR, is indicated in the upper-left corner of each frame (computed relative to the Brα rest wavelength λ₀ = 4.0523 μm). The systemic velocity of 18 km/sec is based on Fe II lines in the optical (Wallström et al. 2017).