SEDs of all NIKA2 sources of interest. Each SED is from a single-component modified black-body adjusted to the Herschel and NIKA2 data by varying the dust temperature T_dust, the bolometric luminosity L_bol, and the dust emissivity index β, and keeping the redshift fixed at z = 2.5 for all sources. Empty markers mark the upper limits. The seven sources in the candidate cosmic filament discussed in this study are labelled in red. is reduced with the number of degrees of freedom ν (see details in Sect. 4).