Upper panel: Mean spectrum of the Balmer shell. This spectrum was extracted from 57 spaxels with at least 3σ Hβ detections. The line (green dashed line), the continuum (orange dashed line), and the full (red line) models are from our q3dfit analysis. The fitted, redshifted [O III] λ5007 and continuum emissions are consistent with noise. Middle panel: Zoom in spectra of the Hγ and Hβ regions. Lower panels: Mean spectra of blueshifted (v₅₀ < −25 km s⁻¹, left) and redshifted (v₅₀ > 25 km s⁻¹, right) Hβ spaxels.