a) NH₃(1, 1) intensity map (^∫T_MBdv) of L1251C. The starting point for the contour levels is 1.2 K km s^-1; the increment is 0.9 K km s^-1. The crosses mark measured positions. The stars indicate the location of the IR sources detected by IRAS. b) NH₃(1, 1) radial velocity field (color map) shown after subtracting the mean radial velocity ⟨ V_LSR ⟩ = −4.80 km s^-1. The NH₃ peak is labeled as in Table 1. The (0, 0) map position is RA = 22:35:53.6, Dec = 75:18:55 (J2000). c) The grey and blue contours show, respectively, the NH₃(1, 1) and N₂H⁺(1–0) intensities integrated over all hyperfine components. The thick contours denote the half-maximum (50%) level, which defines the core size in the corresponding emission line. The N₂H⁺(1–0) data are taken from Fig. 2 of Caselli et al. (2002), where the contour levels are 0.4, 0.7, 1.0, 1.2, 1.5, and 1.8 K km s^-1, and the peak intensity is 1.91 ± 0.12 K km s^-1.