Left: relation between the L_{[C II ]} ∕L_FIR ratio and L_FIR. The values observed for Hyde are shown with a green square. The range of values found in z = 0 luminous infrared galaxies are indicated with the hashed region (Díaz-Santos et al. 2013). High-redshift galaxies from the literature are shown with colored circles: light blue for the z = 2 galaxies of Brisbin et al. (2015), dark blue for the lensed z = 2 galaxy studied in Schaerer et al. (2015), red for the z = 4.5 SMGs found near quasars in Trakhtenbrot et al. (2017), purple for the z = 5 LBGs of Capak et al. (2015), and finally orange a collection of galaxies at z = 3–5 (Cox et al. 2011; De Breuck et al. 2011; Valtchanov et al. 2011; Swinbank et al. 2012; Walter et al. 2012; Wagg et al. 2012; Riechers et al. 2013, 2014; Gullberg et al. 2015; Oteo et al. 2016). Galaxies from Brisbin et al.(2015) and Gullberg et al.(2015) with unknown magnification factors were assumed to have μ = 10 (the average of the published magnifications from both samples). When needed, we assumed L_FIR = L_IR∕1.5. Right: relation between the offset from the main sequence (SFR ∕SFR_MS) and the stellar mass for the galaxies on the left with measured masses. If no stellar mass estimate was available, we inferred it from the dynamical mass assuming a gas fraction of 50%. The value of SFR_MS was taken from Schreiber et al. (2015) at z < 3.5 and Schreiber et al. (2017) at 3.5 ≤ z ≤ 4.5; values at higher redshifts were estimated assuming a redshift dependence of . On this plot, we also show with purple circles the two z = 6.6 LBGs of Smit et al. (2018), which are detected in [C II] but not in the FIR continuum, and thus for which the SFR is based only on the UV luminosity. We also show the position of z = 4 main sequence galaxies from Schreiber et al. (2017) as small green squares; these galaxies have no [C II] measurement. The 90% confidence region for Hyde is shown in light green, and the most conservative upper limit of Jekyll (SFR < 13 M_⊙ yr⁻¹ at 3σ, as obtained from SFR_IR) is shown with a blue arrow for reference.