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Paper: Spectral Variability of Quasars in the Optical Band
Volume: 284, AGN Surveys, IAU Colloquium 184
Page: 81
Authors: Trèvese, Dario; Vagnetti, Fausto
Abstract: A new analysis of the spectral variability of quasars has been performed on the basis of B and R light curves of 42 PG quasars, made available by the Wise Observatory group. We introduce a spectral variability parameter measuring the change of spectral slope per unit brightness variation. We compute the variations of the spectral energy distribution (SED) due to: i) a change of relative intensity of host galaxy and nuclear spectra of fixed shapes; ii) a global change of accretion rate onto a geometrically thin disk. None of these models is able to account completely for the observed spectral variations. This suggests that spectral variations are intrinsic of the nuclear component and caused by local perturbations.
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