Comparison of L_{[CI]369 μm}/L_TIR and dust temperature (T_dust) observed in systems PJ231−20 and PJ308−21 with various local and high-z galaxies. Data points are color-coded by log L_TIR. The reported sample is taken from Valentino et al. (2020) (and references therein) and comprises local star-forming (SF) galaxies (circles) and AGN (diamonds); main-sequence (MS) galaxies (upright triangles) and starburst galaxies (upside-down triangles) at z ∼ 1; and z ∼ 2 − 4 SMGs (pentagons) and QSOs (squares). The QSO PJ231−20 and its companion are indicated with stars, and the PJ308−21 sources are marked with crosses. For the companions we report the cases with an assumed dust temperature of 47 K and 35 K. These points are connected by a dashed line. The upper limit in our sources corresponds to 3σ. We also report measurements in quasar ULAS J1342+0928 at z = 7.54 (see Novak et al. 2019) and quasar J0439+1634 at z ≃ 6.5 (Yang et al. 2019a).