2002A&A...387..838D

BeppoSAX observed the Seyfert 1 galaxy NGC 3783 for ∼5 days from 1998 June 6 to 1998 June 10. The average flux during the observation was F_2–10keV∼6x10^–11erg/cm²/s. The long exposure provided a very high quality spectrum that exhibits all the typical features of Seyfert 1s. The high energy cut-off of the intrinsic continuum, at E_c=340±⁵⁶⁰₁₀₇keV, was detected for the first time in this object. During the observation the source showed modest flux variations (∼20% in 2-10keV) and spectral variability that can be completely explained by a change of the intrinsic slope ΔΓ∼0.1. NGC 3783 is one of the few Seyfert 1s that exhibits a soft emission component in the BeppoSAX spectrum. This soft excess is well reproduced by a black body component with temperature kT∼0.2keV. A warm absorber is also required to fit the soft X-ray spectrum. Both reprocessing features, the Compton reflection hump and the Fe emission line, were detected in our observation. In addition to a narrow iron line (as observed by Chandra) a broad component with σ=0.72±^1.28_0.27keV and EW=115±76 eV, is required to fit the line. The observed Compton hump and the Fe line are well reproduced with the ionized (logξ=2.73±^0.04_0.05) disc reflection model of Ross & Fabian (1993MNRAS.261...74R). In this case the soft excess observed below 2keV can be accounted for by the disc emissivity and no additional soft X-rays component is required to fit the spectrum.