Contribution
Light element abundances in NGC 5128 from planetary nebulae
Presenter: Jeremy Walsh (European Southern Observatory)
Abstract: Planetary nebulae constitute a unique source of light element abundances for individual stars in a distant stellar population. Multi-slit spectra of 50 planetary nebulae (PN) in NGC 5128 have been observed with the ESO VLT and FORS1 spectrometer. The planetary nebulae were observed in three fields covering a range of galactic radii from 2 to 19 kpc. The emission line spectra have been analysed for light element abundances (He, O, N, Ne, S, Ar). Stacked spectra were formed to determine the average conditions for O abundances of the faint nebulae. The measured range in [O/H] is ∼ 0.4 dex and is sub-solar, resembling the PN population in a Magellanic irregular. The [O/H] dependence with galactic radius is notably flat, but the PN with the highest O abundance occur in the field closest to the nucleus.