Intrinsic 2 − 10 keV luminosity versus column density. Protocluster members are shown in cyan, magenta, and green. Diamonds indicate sources whose properties were derived via spectral fitting, while circles are for sources with properties derived from their hardness ratio (HR). Other classes of AGN detected in the X-ray are shown in different colors (Urrutia et al. 2005; Just et al. 2007; Wang et al. 2013; Banerji et al. 2014; Stern et al. 2014; Assef et al. 2016; Corral et al. 2016; Martocchia et al. 2017; Mountrichas et al. 2017; Ricci et al. 2017; Goulding et al. 2018; Vito et al. 2018a; Zappacosta et al. 2018; Li et al. 2019; Lansbury et al. 2020; Zou et al. 2020). Newly discovered AGN (i.e., not known as such prior to this work) are highlighted with thick black circles.