as a function of FWHM derived from the lowest transition of each PHz-IRAM source with secure redshift (full circles: purple for CO(2−1), cyan for CO(3−2), orange for CO(4−3), and red for CO(5−4)). The large red star represents the median value of all PHz-IRAM sources. Black diamonds represent CO-detected cluster and protocluster galaxies at 1.4 < z < 3.1 and log(L_IR/L_⊙) > 11.44 + 0.5 × z from the literature, and the large filled orange diamond the corresponding median value. Green open triangles represent the observed values for lensed SFGs at 1.4 < z < 3.1 (Harris et al. 2012; Saintonge et al. 2013; Dessauges-Zavadsky et al. 2015; Cañameras et al. 2015; Aravena et al. 2016; Yang et al. 2017; Harrington et al. 2018; Solimano et al. 2021) and the large full green triangle the corresponding median value. The dashed purple line is the best-fit relation for unlensed high-z SMGs from Bothwell et al. (2013), and the red dashed line is the same relation but multiplied by a factor of 5 to match the PHz-IRAM median value. The dotted red line is the best linear fit to the PHz-IRAM values.