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J.R. Gabel, F.C. Bruhweiler (IACS/CUA)
We present photoionization modeling results for the LINER/H II region transition nucleus NGC 4569. Its nuclear UV emission is clearly dominated by a compact, young stellar population (Maoz et al. 1998; Barth et al. 1998) and there are no signatures of an AGN in the multi-wavelength data of NGC 4569. Thus, NGC 4569 is an ideal object for testing a possible link between stellar photoionization and nuclear emission line regions characterized by low ionization. This analysis builds on the photoionization results for NGC 4569 presented by Barth & Shields (2000). We derive rigid constraints on the photoionizing emission through spectral population synthesis of the nuclear starburst, as well as by placing an observationally derived limit on the contribution from hot Wolf-Rayet stars. Additional constraints for our photoionization analysis are obtained from published imagery and spectral data. We find that very specific nuclear conditions are required if stellar photoionization is the sole ionization mechanism. Specifically, at least two spatially distinct emission line components are needed, an inner core of emission coincinding with the compact starburst, as well as an extended component. Furthermore, a separate high denisty component is required to reproduce the strength of the [O I] \lambda6300 emission. We offer a physical interpretation for these results in terms of an evolving starburst.