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The continuum emission is one of the primary channels by which AGN release energy. The physical understanding of the various mechanisms which give rise to the continuum is still rather rudimentary, and at least some of the proposed (textbook) explanations may lack relevance altogether. One significant step forward could be the growing number of multiwavelength, coordinated observational campaigns from observatories both on Earth and in space. In spite of this, the spectral coverage is at present far from complete, leaving the bolometric luminosity undetermined in many sources. The unobserved extreme UV (EUV) region is one particular example.

Non-blazar continuum spectra are often assumed to contain an underlying power law

Equation 5 (5)

with a spectral index alpha ~ 1, extending over a range of 104 in frequency (from IR to X-rays), on top of which various bumps are superposed. A generic AGN spectrum is given in Fig. 2.

Figure 2

Figure 2. A typical AGN continuum (theorist's view). Consistency with the observed y-ray background implies another turnover at higher energies. From Ref. 11.

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