View of the umbral flash inferred from the diffraction limited data. Upper panel: Divided map of temperature T(x, y) (bottom left) and line-of-sight velocity v_los (top right) at z ∼ 1 Mm. The horizontal dotted line represents the slice selected for the three lower panels, and the cross indicates where the umbral flash happens (i.e. where the strongest supersonic velocities are found). Bottom panels: Temperature T(x, z), Mach number M(x, z), and magnetic field B(x, z) on the plane of the slice indicated on the upper panel (y = 88 Mm). As a reference, the curves of constant optical depth log τ_c = 0, −2, −3, −4, −5 are indicated by the dashed black or white lines. Green contours indicate the regions where supersonic flows are found: ∥M > 1∥.