Maps of the dust emission and positions of the NS spectra for each source in the sample. Left: dust emission maps at λ = 1.3 mm (IRAM/30 m) toward L1521E, L1498, and L1544 (Tafalla et al. 2002, 2004), and at λ = 0.5 mm (Herschel/SPIRE) toward L1521B. Contour levels (in MJy sr⁻¹) and HPBW are indicated in each panel. The reference positions (0′′, 0 offsets) are given in Table 1. Right: map of the NS emission line (only the main hyperfine component of the Π⁺ manifold at 115 GHz is shown; see also Fig. 3). The intensity scale (, −0.1 to 0.5 K) is the same for all sources.