The hard X-ray spectrum of the Seyfert galaxy IRAS 18325-5926: cool corona, reflection from an ionized disk and variable iron K emission

K. Iwasawa; J. C. Lee; A. J. Young; C. S. Reynolds; A. C. Fabian

doi:10.1111/j.1365-2966.2004.07206.x

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The hard X-ray spectrum of the Seyfert galaxy IRAS 18325-5926: cool corona, reflection from an ionized disk and variable iron K emission

K. Iwasawa·J. C. Lee·A. J. Young·C. S. Reynolds·A. C. Fabian

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Abstract

We report our analysis of X-ray spectra of the Seyfert galaxy IRAS 18325-5926 (=Fairall 49) obtained from various X-ray observatories prior to XMM-Newton, including new results from two RXTE and one BeppoSAX observations. A relatively steep continuum slope (photon-index of ~2.2) in the 2-15 keV band is confirmed. The continuum spectrum observed with the BeppoSAX PDS shows a possible roll-over at energies above 30 keV, indicating a Comptonizing corona cooler than in other Seyfert nuclei. The X-ray spectrum above 2 keV is best explained with a model including reflection from a highly ionized disk with significant relativistic blurring. The iron K-alpha emission feature is then mainly due to FeXXV. The recent seven observations shows that the iron K emission flux appears to follow the continuum between the observations separated by a few months to years, although some exceptions suggest that the line strength may be determined in a more complex way.

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K. Iwasawa, J. C. Lee, A. J. Young, C. S. Reynolds, A. C. Fabian. 2003-09-16. The hard X-ray spectrum of the Seyfert galaxy IRAS 18325-5926: cool corona, reflection from an ionized disk and variable iron K emission. https://doi.org/10.1111/j.1365-2966.2004.07206.x

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