NGC 5548 was observed by BeppoSAX in a single long (8 day) observation from 0.2 to 200 keV. We find (1) spectral variation of the source produced by a change of the intrinsic power-law slope; (2) a high-energy cutoff at E-c = 115(-27)(+39) keV with a hint of change of E-c with flux; and (3) O VII and O VIII absorption K edges and a possible blended O VII-O VIII K alpha,beta emission feature at 0.54(-0.06)(+0.07) keV, inconsistent with a purely photoionized gas in equilibrium. We propose that the temperature of the absorbing and emitting gas is similar to 10(6) K so that both collisional ionization and photoionization contribute.

Nicastro F, Piro L, De Rosa A, Feroci M, Grandi P, Fiore F, et al. (2000). A long observation of NGC 5548 by BeppoSAX: The high-energy cutoff, intrinsic spectral variability, and a truly warm absorber. THE ASTROPHYSICAL JOURNAL, 536(2), 718-728.

A long observation of NGC 5548 by BeppoSAX: The high-energy cutoff, intrinsic spectral variability, and a truly warm absorber

MATT, Giorgio;
2000

Abstract

NGC 5548 was observed by BeppoSAX in a single long (8 day) observation from 0.2 to 200 keV. We find (1) spectral variation of the source produced by a change of the intrinsic power-law slope; (2) a high-energy cutoff at E-c = 115(-27)(+39) keV with a hint of change of E-c with flux; and (3) O VII and O VIII absorption K edges and a possible blended O VII-O VIII K alpha,beta emission feature at 0.54(-0.06)(+0.07) keV, inconsistent with a purely photoionized gas in equilibrium. We propose that the temperature of the absorbing and emitting gas is similar to 10(6) K so that both collisional ionization and photoionization contribute.
Nicastro F, Piro L, De Rosa A, Feroci M, Grandi P, Fiore F, et al. (2000). A long observation of NGC 5548 by BeppoSAX: The high-energy cutoff, intrinsic spectral variability, and a truly warm absorber. THE ASTROPHYSICAL JOURNAL, 536(2), 718-728.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11590/132466
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 49
social impact