Population diagrams of HNCO, HNCS, HC₃N, and NO for a range of molecular hydrogen densities (n_H2, bottom left corner) and a given input value for the kinetic temperature and total column density (T_kin and N_tot; top right corner); the dotted line connects the LTE points. Only the transitions detected in this work are represented in this diagram (Table 3). For HNCO, the transitions within the K_a = 0 and K_a = 1 ladders are indicated by empty and filled symbols, respectively. For NO, we plot the three hyperfine components with the highest values of the Einstein coefficient (A_ul) for each of the Π⁻ and Π⁺ doublets at 250 and 350  GHz (i.e. at E_u = 19.2 and 36.1 K), the three hyperfine components with the largest A_ul of the Π⁺ band at 150  GHz (i.e. at E_u = 7.2 K) and the Π⁻(3/2,3/2)–(1/2,1/2) line, which is spectrally isolated in our data, at 150 GHz (E_u = 7.2 K). These calculations have been done with a LVG radiative transfer code (MADEX) – see text in this appendix.