Spectral energy distributions of the selected events: E19 at z = 6.5 (first row), E31 at z = 6.8 (second), E36 at z = 7.0 (third), and E52 (last) at z = 8.0, extracted from different LOSs shown as black solid lines in Fig. 5, from an aperture containing the SF region (r_SF = 8.2, 7.4, 5.0, 4.8 kpc, respectively). The synthetic SEDs are compared with the sensitivities of various EM telescopes. The following are shown: LSST filters Z (dark green vertical line) and Y (red vertical line); Roman (brown horizontal line); JWST NIRCAM (orchid-coloured dots); JWST-MIRI (green curved line, for an exposure time of ∼3 h); Origins-like (grey horizontal lines, at 5σ in 1 hour), SPICA-like (red, blue, green boxes; yellow and magenta horizontal lines at 5σ in 1 h, represented by the top portions of the rectangles, and at 3σ by the lower sides of the rectangle; when the confusion limit is reached within an hour, sensitivities are indicated by the lines); ALMA (blue curved line, 10 h); and AtLAST (light green horizontal line).