PV plots of the SO emission in IRAS 21078+5211 at positions offset from the disk midplane. The upper and lower panels present the PV plots of the SO 6₅–5₄ line along the direction at PA = 140° (marked by the dashed black line in Figs. 1 and 2) at positions along the disk rotation axis $0_{\cdot }^{\mathrm{\prime }\mathrm{\prime }}2$ (i.e., the beam major axis) above (northeast) and $0_{\cdot }^{\mathrm{\prime }\mathrm{\prime }}2$ below (southwest) the disk midplane, respectively. PV plots are shown with color maps and white contours, with contour levels ranging from |I_min|/2 to I_max at steps of |I_min|/4, where I_min and I_max are the minimum and maximum of the map, respectively. In each panel, the vertical and horizontal white axes denote the positional offset ($\approx 0_{\cdot }^{\mathrm{\prime }\mathrm{\prime }}8$) of the YSO relative to the phase center of the observations and YSO V_LSR (≈ −6.1 km s⁻¹), respectively. For comparison, the red curve shows the Keplerian velocity profile for a central mass of 6 M_⊙. In the lower left corner of the panels, the vertical cyan and horizontal white error bars indicate the velocity and spatial resolutions, respectively.