ROSAT Evidence for Intrinsic Oxygen Absorption in Cooling Flow Galaxies and Groups

摘要: The existence of large quantities gas that have cooled and dropped out the hot phase in massive elliptical galaxies, groups, clusters is key prediction inhomogeneous cooling flow scenario. Using spatially resolved, deprojected ROSAT Position Sensitive Proportional Counter (PSPC) spectra 10 brightest galaxies groups with low Galactic column densities, we detected intrinsic absorption over energies ~0.4-0.8 keV at 2 σ/3 σ level half sample. Since no indicated for below ~0.4 keV, most reasonable model absorber collisionally ionized temperatures T = 105-6 K arising from states oxygen but a significant contribution carbon nitrogen. soft X-ray emission this warm can also explain sub-Galactic densities cold inferred within central regions systems. (This could not be explained by an composed only dust.) Attributing to reconciles columns H He Einstein ASCA lack such ROSAT. Within ~10-20 kpc, where constraints are secure, mass consistent (perhaps all) matter deposited lifetime flow. produces or absorption, masses negligible atomic molecular I CO observations flows. It found if × 105 K, then optical far-ultraviolet implied does violate published constraints. An important theoretical challenge understand how temperature maintained supported gravitationally, discuss possible solutions these problems would require fundamental modification standard Finally, as product dropout other flows verified new Chandra XMM observations.