What Can We Learn About the Kinematics of Bright Extragalactic Planetary Nebulae?

Abstract

We present high resolution spectroscopy in the [O III] λ5007 and Hα lines of bright planetary nebulae in the Milky Way bulge and the dwarf galaxies M32, Fornax, Sagittarius, and NGC 6822 obtained at the Observatorio Astronómico Nacional in the Sierra San Pedro Mártir using the Manchester Echelle Spectrograph. We use the high signal-to-noise (S/N) observations of Milky Way bulge planetary nebulae to explore what kinematic information can be determined reliably when observing extragalactic planetary nebulae in the [O III] λ5007 line at modest S/N.We nd that the intrinsic line widths measured in [O III] λ5007 and Hα are very similar. Over
the range of S/N available in this sample, the line width we measure is independent of the S/N. Finally, deviations from a Gaussian line shape are small. Thus, the line width of the [O III]λ5007 line in bright extragalactic planetary nebulae should reflect the kinematics of most of the mass in the ionized nebular shell.