A survey of 3.3 micron PAH emission in planetary nebulae using FLITECAM

Abstract

AbstractWe have performed a study of 3.3 micron PAH emission in planetary nebulae using ground-based observations with FLITECAM, one of a suite of instruments designed for airborne astronomy aboard SOFIA, NASA's Stratospheric Observatory for Infrared Astronomy. The survey was performed on the Shane 3 meter telescope at Lick Observatory as part of the ground-based commissioning of the FLITECAM grism spectroscopy mode. Spectral resolution of R ~ 1700 was obtained with direct-ruled KRS-5 grisms. Targets included AGB stars and sources showing PAH emission in KAO, ISO or IRAS observations. Additionally, several oxygen-rich nebulae were observed in order to test methodology. Twenty objects were surveyed, of which 11 showed PAH emission. In objects exhibiting PAH emission, the relationship between the nebular C/O ratio and PAH equivalent width was found, showing a detectable PAH emission cutoff at a nebular C/O ratio of 0.65 ± 0.28. Selected objects with detected PAH emission were further investigated to trace PAH emission spectral variation within individual nebulae.