SFE (≡ ) as a function of L_IR for ALMA IDs 3 and 8 (blue filled stars), and for sources from the literature with 1 <  z <  3 (black filled squares: cluster galaxies, black filled triangles: proto-cluster galaxies, green open circles: SMGs, purple open circles: AGN, and red open circles: obscured AGN; see Sect. 6.3). The solid and dashed lines represent, respectively, the average relations for MS and SB galaxies derived by Sargent et al. (2014) and given in Eqs. (5) and (6).