A Long Observation of NGC 5548 byBeppoSAX: The High‐Energy Cutoff, Intrinsic Spectral Variability, and a Truly Warm Absorber

Fabrizio Nicastro, Luigi Piro, Alessandra De Rosa, Marco Feroci, Paola Grandi, Fabrizio Fiore, Martin Elvis, Francesco Haardt, Jelle Kaastra, Angela Malizia, Laura Maraschi, Giorgio Matt (+2 others)
2000 Astrophysical Journal  
NGC 5548 was observed by BeppoSAX in a single long (8 day) observation from 0.2 to 200 keV. We find (1) the spectral variation of the source is produced by a change of the intrinsic power law slope; (2) a high energy cut-off at E_c= 115^+39_-27 keV with a hint of change of E_c with flux; (3) OVII and OVIII absorption K edges, and a possible blended OVII-OVIII Kα,β emission feature at 0.54^+0.07_-0.06 keV, inconsistent with a purely photoionized gas in equilibrium. We propose that the
more » ... of the absorbing and emitting gas is ∼ 10^6 K so that both collisional ionization and photoionization contribute.
doi:10.1086/308950 fatcat:4rw5grj7qzhxdhfr4srybsvc6q