Curvelet component of the column density map of the Aquila field around the Serpens South filaments taken from André et al. (2010). The curvelet component is obtained using a morphological component analysis algorithm (MCA, from Starck et al. 2003) which enhances the contrast of the filamentary structure against the more diffuse background of the cloud. The positions of the observed spectra are plotted in red squares and blue triangles for N₂H⁺ and C¹⁸O, respectively. The numbers correspond to the filaments listed in Table 1 and are given at the upper right of the spectra in Fig. A.4 and some of the spectra of Fig. A.7.