Soft X-ray data from the ROSAT Position Sensitive Proportional Counter (PSPC) were retrieved from the public archive situated at the NASA Goddard Space Flight Center. We chose the longest of the two available PSPC observations of this object. This observation started on 1992-January-29 and collected a total of 8500s of good data. A PSPC spectrum of MCG-6-30-15 was formed by binning all counts extracted from a circular region of radius 2arcmin centered on the point source corresponding to MCG-6-30-15. The background count rate within this region is found to be negligible compared with the source.
These data have been previously discussed by Nandra & Pounds (1992).
These authors found evidence for a notch in the PSPC spectrum at an energy
of 
. They interpreted this feature as a blend of OVII and OVIII K-shell absorption edges resulting from
highly-ionized material along the line of sight to the primary (power-law)
X-ray source. This material has become known as the warm absorber
(Halpern 1984), and shall play a major role in the discussion presented in
this paper.