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We consider in detail the spectral energy distribution (SED) andmulti-wavelength variability of NGC5548. Comparison with the SEDs of other AGNsimplies that the internal reddening of NGC5548 is E(B-V) = 0.17 mag. Theextinction curve is consistent with the mean curve of other AGNs found byGaskell & Benker, but inconsistent with an SMC-type reddening curve. Becausemost IR emission originates exterior to the broad-line region (BLR), the SEDseen by the inner BLR is different from that seen by the outer BLR and from theearth. The most likely BLR covering factor is ~ 40% and it is not possible toget an overall BLR covering factor of less than 20%. This requires that the BLRis not spherically symmetric and that we are viewing through a hole.Line-continuum variability transfer functions are consistent with thisgeometry. The covering factor and geometry imply that near the equatorial planethe BLR covering approaches 100%. The spectrum seen by the outer regions of theBLR and by the torus is thus modified by the absorption in the inner BLR. Thisshielding solves the problem of observed BLR ionization stratification beingmuch greater than implied by photoionization models. The BLR obscuration alsoremoves the problem of the torus covering factor being greater than the BLRcovering factor, and gives consistency with the observed fraction of obscuredAGNs. The flux reduction at the torus also reduces the problem of AGNdust-reverberation lags giving sizes smaller than the dust-sublimation radii.

NGC 5548: The AGN Energy Budget Problem and the Geometry of the Broad-Line Region and Torus