R100 spectra of three newly identified galaxies with z < 3 found in the FoV of SPT0311–58, together with the bright foreground (lens) galaxy. The labels indicate their redshifts (see text). For lz2 and lz3 the insets show the dependence of residuals (reduced χ²) as a function of the redshift, for the fits performed with EAZY (Brammer et al. 2008). The horizontal blue line in the inset marks ${\chi }_{\text{red}}^2=1$. The sky background spectrum inferred from ∼1550 spaxels free from galaxy emission is also shown in the bottom panel.