We present a detailed X-ray study of the broad-line radio galaxy 3C 382, observed with the BeppoSAX satellite in a very bright state. The continuum emission is well modeled with a power law that steepens at high energies, with an e-folding energy of similar to 120 keV. At soft energies a clear excess of emission is detected, which cannot be explained solely by the extended thermal halo seen in a ROSAT / HRI image. A second, more intense soft X-ray component, possibly related to an accretion disk, is required by the data. Both a reflection component (Omega /2 pi = 0.3) and an iron line (EW similar to 50) are detected at levels much weaker than in Seyfert galaxies, suggesting a common origin. Combining our measurements with results from the literature we find that the iron line has remained approximately constant over 9 yr while the continuum varied by a factor of 5. Thus, the fluorescent gas does not respond promptly to the variations of the X-ray continuum, suggesting that the reprocessing site is located away from the X-ray continuum, likely at parsec distances. While the continuum shape indicates that X-rays derive from a thermal Comptonization process, the weakness of other spectral features implies that either the upper layers of the optically thick accretion disk are completely ionized or the corona above the disk is outflowing with mildly relativistic velocity.
Grandi, P., Maraschi, L., Urry, C.m., Matt, G. (2001). Weak reprocessed features in the broad-line radio galaxy 3C 382. THE ASTROPHYSICAL JOURNAL, 556(1), 35-41 [10.1086/321546].
Weak reprocessed features in the broad-line radio galaxy 3C 382
MATT, Giorgio
2001-01-01
Abstract
We present a detailed X-ray study of the broad-line radio galaxy 3C 382, observed with the BeppoSAX satellite in a very bright state. The continuum emission is well modeled with a power law that steepens at high energies, with an e-folding energy of similar to 120 keV. At soft energies a clear excess of emission is detected, which cannot be explained solely by the extended thermal halo seen in a ROSAT / HRI image. A second, more intense soft X-ray component, possibly related to an accretion disk, is required by the data. Both a reflection component (Omega /2 pi = 0.3) and an iron line (EW similar to 50) are detected at levels much weaker than in Seyfert galaxies, suggesting a common origin. Combining our measurements with results from the literature we find that the iron line has remained approximately constant over 9 yr while the continuum varied by a factor of 5. Thus, the fluorescent gas does not respond promptly to the variations of the X-ray continuum, suggesting that the reprocessing site is located away from the X-ray continuum, likely at parsec distances. While the continuum shape indicates that X-rays derive from a thermal Comptonization process, the weakness of other spectral features implies that either the upper layers of the optically thick accretion disk are completely ionized or the corona above the disk is outflowing with mildly relativistic velocity.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.