Typical example of one set of observed optical/UV (Swift UVOT and HST COS) and X-ray (Swift XRT) spectra of NGC 5548, which were fitted with the broadband spectral model described in Sect. 3. The UVOT fluxes are from six photometric filters and the HST COS fluxes are from five narrow energy bands in the UV continuum. Residuals of the fit, defined as (observed−model)/model, are shown in the bottom panel. The displayed data are from a 10-day bin period between 2−12 March 2014.