Oxygen absorption in cooling flows

The inhomogeneous cooling flow scenario predicts the existence of large qua ntities of gas in massive elliptical galaxies, groups, and clusters that ha ve cooled and dropped out of the flow. Using spatially resolved, deprojecte d X-ray spectra from the ROSAT PSPC, we have detected strong absorption ove r energies similar to 0.4-0.8 keV intrinsic to the central similar to 1' of the galaxy NGC 1399, the group NGC 5044, and the cluster A1795. These syst ems have among the largest nearby cooling flows in their respective classes and low Galactic columns. Since no excess absorption is indicated for ener gies below similar to 0.4 keV, the most reasonable model for the absorber i s warm, collisionally ionized gas with T = 10(5)-10(6) K in which ionized s tates of oxygen provide most of the absorption. Attributing the absorption only to ionized gas reconciles the large columns of cold H and He inferred from Einstein and ASCA with the lack of such columns inferred from ROSAT an d also is consistent with the negligible atomic and molecular H inferred fr om H I and CO observations of cooling flows. The prediction of warm ionized gas as the product of mass dropout in these and other cooling flows can be verified by Chandra and X-Ray Multimirror Mission.