Left: dust continuum map at observed 888 μm (rest-frame 125 μm) of the QSO ULAS J131911. For a redshift of z = 6.1330 (based on a [CII] 158 μm detection by Wang et al. 2013) this corresponds to a rest-frame wavelength of 124.5 μm. The white contours corresponds to S/N = 5, 10, 20, 40, and 80σ. The synthesized beam (θ = 0.63″ × 0.44″) is shown in the lower left corner. Right: dust continuum SED combining photometric measurements at rest-frame wavelengths 125 μm (our work), 158 μm (Shao et al. 2017), and 168 μm (Wang et al. 2013). The solid blue line corresponds to the best modified blackbody fit to the data. This yields a dust temperature of T_dust = 56.7 K and dust mass of M_dust = 10^8.73M_⊙. The shaded region indicates the 2.5 and 97.5 percentile for the spread of model SEDs based on the posterior distributions for the parameters.