AAS 195th Meeting, January 2000
Session 117. Active Galactic Nuclei: Modelling and Theory
Display, Saturday, January 15, 2000, 9:20am-4:00pm, Grand Hall

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[117.01] Excitation Mechanism in the LINER/Starburst Galaxy NGC 4569

J.R. Gabel, F.C. Bruhweiler (IACS/CUA)

We present an analysis of the low ionization nuclear emission line region (LINER)/Transition galaxy, NGC 4569, to determine the excitation mechanism in the compact nuclear region. Motivated by the clear presence of hot stars seen in the FOS/HST UV spectrum, we model the history and nature of the nuclear stellar population. Comparing the shape of the UV continuum to the spectra of O stars gives an extinction of EB-V~0.6, consistent with the value determined from emission line analysis. We apply single burst population synthesis modeling to the UV spectrum to determine an age of ~ 5-6 Myr for the nuclear starburst. Published results show that the X-ray emission is consistent with normal processes associated with a young stellar population. Optical emission line fluxes are obtained from results published by Ho et al. (1997) and upper limits on UV line strengths are determined from the FOS UV data. Using the above results, we apply photoionization modeling analysis to determine if the emission line spectrum of NGC 4569 is consistent with photoionization by the nuclear stellar population. We discuss the implications of these results for a range of different classes of emission line galaxies - LINERs, Transition objects, and nuclear H II galaxies.

The author(s) of this abstract have provided an email address for comments about the abstract: gabel@iacs.gsfc.nasa.gov

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