3D representation of the intrinsic properties of E31 at z = 6.8. Each box has a side of 20 pkpc and 1.2 pkpc along the z-, y-, and x-directions (in the left, middle, and right panel, respectively) for three different LOSs. First row: Gas density of the star-forming particles. The black circle identifies the region adopted to compute the intrinsic properties in Sect. 3.1, corresponding to 30% of the virial radius. The filled black circles represent the location of the MBHs in the simulation. In particular, the location of the merger event is denoted by a yellow-filled star. The location of the MBHs and of the merger event remain the same for all rows. To avoid clutter and to provide a better view of the host galaxy’s intrinsic properties, the black-filled circles and the yellow-filled star are presented only in the first row. Second row: Star formation rate of the SF particles. Third row: Gas metallicity of the SF particles. Fourth row: Gas velocity of the SF particles along the different LOS considered.