(a) Integrated-intensity map of HCN (J = 4–3) for Neptune. The white ellipse at the bottom left illustrates the shape of the synthesized beam. (b) HCN intensity profiles along the 1.″05 and 0 .″75 radius circles indicated by white dashed lines in (a). (c) Radial HCN intensity profile (blue dots) and averaged profile (red curve). Horizontal and vertical error bars are the same as the synthesized beam size, ∼0.″2 and 0.2 Jy beam⁻¹ km s⁻¹, respectively.