SED for the source powering the ELAN MAMMOTH-1 at z = 2.319 (source B in Cai et al. 2017b). The data-points are from LBT/LBC imaging and UKIRT/WIRCAM (Cai et al. 2017b and Xu et al. in prep.; blue), AllWISE source catalog (Wright et al. 2010; orange), our SCUBA-2 observations (magenta), and the FIRST survey (Becker et al. 1994; green). Left panel: data-points in comparison to the SED of M 82 (Silva et al. 1998; black line), of the average ALESS SMGs (dashed brown line), and of the average ALESS SMGs with A_V <  1 (da Cunha et al. 2015; yellow), best fitting our data-points for z = 2.319. The best agreement is found for the M82 template, but the W3 data-point is underestimated. Right panel: data-points in comparison to the best fit of AGNfitter (gray line), together with the individual components: hot dust emission (purple), cold dust emission (green), stellar emission (yellow), and the emission from the accretion disk (blue). The hot dust contribution allows a better fit to the data.