Spectral observations of W26 and neighbouring stars. a) Radial velocity of the Hα (black dots) and [N II] (blue triangles) lines along the slit in the W26 co-moving reference system (~−32 km s^-1), with position measured relative to W26. The directions along the slit are also indicated: WNW for Westnorthwest and ESE for Eastsoutheast. b) Line brightness (intensity) in the two spectral lines along the slit (arbitrary units). c) Fitted Gaussian linewidth, σ in the two spectral lines along the slit. The three stars included in the slit, and no further away than 0.4 arcmin from W26, are labelled according to Negueruela et al. (2010).