ChJAA Vol 2, No 4 (2002) / Zou

The Variabilities of the Soft and Hard X-ray Components of NGC 7314 and NGC 7582 and the Distribution of Absorbing Matter in Type II AGNs   

Xiang-Hua Zou, Sui-Jian Xue

Abstract

ASCA observations of the two Type II AGNs, NGC 7314 and NGC 7582, show clear variations in the broad X-ray band (0.4 –10 keV) on short timescales ∼104 s. Spectral analysis indicates that they both have an absorbed hard X-ray component and an unabsorbed soft ``excess" component. To clarify the origin of the latter, we made a cross-correlation analysis of the two components. The results show that, for NGC 7314, the soft X-ray variability is proportional to that of the hard X-ray component. This indicates that the active nucleus of NGC 7314 must be partially covered and so the soft emission is a ``leaking" of the variable hard component. For NGC 7582, there is no detectable variability in the soft component, although there is a definite one in the hard component. This indicates that the variable nucleus of NGC 7582 must be fully blocked by absorbing matter, and the soft emission is most likely the scattered component predicted by the AGN unified model.

Keywords


galaxies: individual (NGC 7314, NGC 7582) --- galaxies: X-rays --- galaxies: variabilities

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