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A complete view of the broad-line radio galaxy 4C+74.26 with XMM-Newton

D. R. Ballantyne

astro-pharXiv:astro-ph/0506673

Abstract

This paper presents a timing study and broadband spectral analysis of the broad-line radio galaxy 4C+74.26 based on a 35 ks XMM-Newton observation. As found in previous datasets, the source exhibits no evidence for rapid variability, and its 0.2-10 keV lightcurve is well fit by a constant. An excellent fit to the pn 0.3-12 keV spectrum was found using a continuum that combines an ionized and a neutral reflector, augmented by both cold and warm absorption. There is no evidence for a soft excess. The column of cold absorption was greater than the Galactic value with an intrinsic column of \~1.9× 1021 cm-2. Evidence for the warm absorber was found from O VII and O VIII absorption edges with maximum optical depths of τO VII=0.3 and τO VIII=0.03, respectively. A joint pn-MOS fit increased the O VIII optical depth to τO VIII=0.1. A simple, one-zone warm absorber model yielded a column of ~9× 1020 cm-2 and an ionization parameter of \~60. Partial covering models provide significantly worse fits than ones including a relativistically broadened Fe K line, strengthening the case for the existence of such a line. On the whole, the X-ray spectrum of 4C+74.26 exhibits many features typical of both a radio-loud quasar (excess absorption) and radio-quiet Seyfert~1 galaxies ( emission and warm absorption). We also show that a spurious absorption line at ~8 keV can be created by the subtraction of an instrumental Cu Kαemission line.

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