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The swan song: the disappearance of the nucleus of NGC 4051 and the echo of its past glory

M. Guainazzi·F. Nicastro·F. Fiore·G. Matt·I. McHardy·A. Orr·P. Barr·A. Fruscione·I. Papadakis·A. N. Parmar·P. Uttley·G. C. Perola·L. Piro
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Abstract

BeppoSAX observed the low-luminous Seyfert 1 Galaxy NGC4051 in a ultra-dim X-ray state. The 2-10 keV flux (1.26 x 10^{-12} erg/cm^2/s) was about 20 times fainter than its historical average value, and remained steady along the whole observation (~2.3 days). The observed flat spectrum (Γ~ 0.8) and intense iron line (EW ~600 eV) are best explained assuming that the active nucleus has switched off, leaving only a residual reflection component visible.

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M. Guainazzi, F. Nicastro, F. Fiore, G. Matt, I. McHardy, A. Orr, P. Barr, A. Fruscione, I. Papadakis, A. N. Parmar, P. Uttley, G. C. Perola, L. Piro. 1998-07-22. The swan song: the disappearance of the nucleus of NGC 4051 and the echo of its past glory. https://doi.org/10.1046/j.1365-8711.1998.02089.x

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