ROSAT observations of LINERs

Results of recent ROSAT observations of five LINERs—NGC 3998, NGC 4579, NGC 3079, NGC 2639, and Pictor A—are presented. Except for NGC 3079, the x‐ray sources are unresolved. The emission from NGC 3079 is dominated by a point source, but also shows extended emission, including (at energies ≲0.5 keV) a ‘‘patch’’ of emission likely associated with the galaxy superwind. No significant short timescale variability was observed. Results of spectral fitting were inconclusive. Pure power law models appear to be ‘‘disfavored,’’ but can only be rejected for NGC 3079 and NGC 3998. Spectral indices for the pure power law models are steeper than the average Γ∼1.7 for AGN at higher energies, but adding, e.g., a component of coronal plasma emission allows the power law component to flatten. For the most part, thermal models also give acceptable fits. Independent of spectral model, it is clear that high intrinsic absorbing columns and strong soft x‐ray excesses are not observed.