Dependences of oxygen abundances 12 + logO/H on (a) stellar masses M_⋆ and on (b) SFR^−0.5 M_⋆ for the samples of CSFGs and high-z SFGs. The maximum likelihood relation to SDSS data in (b) is shown by the straight solid line. The black line in (a) is the relation for z = 0 SDSS SFGs by Mannucci et al. (2010). Large symbols represent high-z SFGs by Amorín et al. (2017) (z = 2.4–3.5, asterisks), Erb et al. (2016) (z ∼ 2.3, filled circles), Troncoso et al. (2014) (z ∼ 3–5, open circles), Onodera et al. (2016) (z ∼ 3–3.7, crosses), Cullen et al. (2014) (z > 2, open triangles) and Jones et al. (2020) (z = 7.1–9.1, filled squares). The meanings of symbols for SDSS CSFGs in both panels are the same as in Fig. 1.