Single-component dust models for B6 and B7 (a redshift of 2.38 is adopted). The black solid lines show the thermal dust continuum emission of the 70 K dust components for both B6 and B7. The open circles represent the measurements at our five Herschel  bands and the filled circles indicate the flux densities at 24 μm (Colbert et al. 2006). The filled square denotes the flux density (or its upper limit) at 870 μm, taken from Beelen et al. (2008). The wavelengths at the rest frame are labeled on the top. For the single-component dust models adopted in the figure (see Sect. 3.4 for details of the dust models.), the χ² values are 1.1 for B6 and 1.0 for B7, respectively. In Sect. 3.3, four typical starburst templates, NGC 6240, M 82, Mrk 231, and Arp 220 (Polletta et al. 2007), are adopted to estimate the redshifts for B6  and B7, and their best fits are overlaid in colored lines.