WARM ABSORBER, REFLECTION, AND FE-K LINE IN THE X-RAY-SPECTRUM OF IC-4329A

Results from the X-ray spectral analysis of the ASCA (Astro-D) perform ance verification (PV) phase observation of the: Seyfert 1 galaxy IC 4 329A are presented. We find that the 0.4-10 keV spectrum of IC 4329A i s best described by the. Sum of a steep (Gamma similar to 1.98) power- law spectrum passing through a warm absorber plus a strong reflection component and associated Fe K line, confirming recent results (Madejsk i et al. 1995; Mushotzky et al. 1995): Further cold absorption in exce ss of the Galactic value and covering the entire source is also requir ed by the data, consistent with the edge-on galactic disk and previous X-ray measurements. The effect of the warm absorber at soft X-ray ene rgies is best parameterized by two absorption edges, one consistent wi th O VI, O VII, or N VII, the other consistent with O VIII. A descript ion of the soft excess in terms of blackbody emission, as observed in some other Seyfert 1 galaxies, is ruled out by the data. A large amoun t of reflection is detected in both the gas scintillation imaging spec trometer (GIS) and the solid-state imaging spectrometer (SIS) dectecto rs, at similar intensities. We find a strong correlation between the a mount of reflection and the photon index, but argue that the best solu tion for the present data is that given by the best statistical fit. T he model dependence of the Fe K line parameters is also discussed. Our best fit gives a slightly broad (sigma similar or equal to 0.11 +/- 0 .08 keV) and redshifted (E similar or equal to 6.20 +/- 0.07 keV) Fe K line, with equivalent width (EW) similar or equal to 89 +/- 33 eV. Th e presence of a weak Fe K line with a strong reflection can be reconci led if one assumes iron underabundances or ionized reflection. We also have modeled the line with a theoretical line profile produced by an accretion disk. This yields results in better agreement with the const raints obtained from the reflection component.