Relation between log N_H and λ_Edd for the eFEDS–W4 sample. The yellow star represents the ELIRG (Toba et al. 2021b), and the orange square shows the location of XID439 (see text). Objects with red circles have optical spectra from SDSS DR16. Typical uncertainties in log N_H and λ_Edd are shown at the bottom right. The dotted line denotes the effective Eddington limit (; Fabian et al. 2006) for different values of N_H (Fabian et al. 2009; Ricci et al. 2017). The pink shaded area represents the blow-out region, in which the dusty gas that produces the nuclear obscuration is expected to be pushed away by radiation pressure (i.e., ). The solid line shows the evolutionary track calculated by Yutani et al. (2021), color-coded by time in units of Myr.