Study of the Soft Excess / Warm Absorber in a Sample of AGN

GTA sample of AGN showing structure in their soft Xrayspectra is to be observed. The physics of the spectralstructure may be 1) a soft excess component above theunderlying power law, possibly from the emission of theaccretion disk, or/and 2) selective absorption due to awarm absorber. The candidate objects have been selected by a systematic study of ROSAT PSPC spectra in comparisonto hard (210 keV) spectra measured by HEAO1, EXOSATor Ginga.