| Abstract |
Accurate emission line fluxes from planetary nebulae (PNe) provide
important constraints on the nature of the final phases of stellar
evolution. Large, evolved PNe may trace the latest stages of PN
evolution, where material from the AGB wind is returned to the
interstellar medium. However, the low surface brightness and spatially
extended emission of large PNe have made accurate measurements of line
fluxes difficult with traditional long-slit spectroscopic techniques.
Furthermore, distinguishing these nebulae from H II regions, supernova
remnants, or interstellar gas ionized by a hot, evolved stellar core can
be challenging. Here, we report on an ongoing survey of large Galactic
PNe (r > 5') with the Wisconsin H-Alpha Mapper (WHAM), a Fabry-Perot
spectrograph designed to detect faint diffuse optical emission lines
with high sensitivity and spectral resolution. Our sample includes newly
revealed Hα enhancements from the AAO/UKST and WHAM Hα
surveys of Parker et al. and Haffner et al. We present accurate emission
line fluxes of Hα, [N II]λ6583, and [O III]λ5007,
and compare our data to other measurements. We use the emission line
ratios and kinematics of the ionized gas to assess, or in some cases
reassess, the identification of some nebulae. |