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St. Komossa (Max-Planck Institut für extraterr. Physik, Garching), S. Mathur (The Ohio State University)
PG\,1404+226 belongs to the class of Narrow-Line Seyfert\,1 galaxies which are characterized by steep soft X-ray spectra, narrow optical Balmer lines and strong FeII emission. The X-ray spectrum of PG\,1404+226 shows an interesting peculiarity: an absorption feature around ~1.1 keV (Ulrich & Molendi 1996) of presently unclear origin. {\em Warm absorbers}, observed in the X-ray spectra of many AGN, do show such features, but the strongest absorption edges in case of {\em solar} metal abundances are those of Oxygen located at lower energies, around 0.74 (OVII) and 0.87 (OVIII) keV. In addition, the UV spectrum of PG\,1404+226 exhibits a quite strong absorption line of NV. We explore interpretations of these unusual UV-X-ray properties in terms of non-solar metal abundances of the absorbing gas. X-ray spectral fits are combined with a UV curve of growth analysis, employing the equivalent widths measured by Ulrich et al. (2000). We then examine how the multiphase broad-line-region cloud equilibrium changes in dependence of elemental abundances and X-ray continuum shape. Finally, we discuss consequences for the evolutionary state of PG\,1404+226 and Narrow-line Seyfert\,1 galaxies in general, based on the recent work of Mathur (2000).
The author(s) of this abstract have provided an email address for comments about the abstract: skomossa@xray.mpe.mpg.de