H¹²C¹⁴N (HCN) J = 1 → 0 channel maps with the crosses indicating (as in case of Figs. A.2–A.6) the position of the radio continuum peak. The spacing between tick marks along the y-axis corresponds to 10″. Central barycentric velocities in km s⁻¹ are given in the upper left corners of each map. The systemic velocity is near 571 km s⁻¹ (Sect. 2). The wedge provides intensities in units of Jy beam⁻¹. We note the dark areas between 525 and 650 km s⁻¹, where the line is seen in absorption. The large-scale rotation of the highly inclined galaxy is such that emission at low velocities is mainly originating from the southwest of the center, while high velocity emission arises from the northeast. The value 0.1 Jy corresponds to ≈4.0 K main beam brightness temperature. The value 1″ represents a projected linear scale of 19 pc. The beam size is shown in the lower right corner of the figure.