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A. Kniazev (ESO / MPIA), E. Grebel (U of Basel / MPIA), D. Zucker, E. Bell, H.-W. Rix, D. Martinez-Delgado (MPIA), H. Harris (USNO)
We present the latest results from our project to search for new planetary nebulae in nearby galaxies using Sloan Digital Sky Survey (SDSS) imaging data. Planetary nebulae (PNe) are an ideal probe of the dynamics of low to intermediate mass stars in nearby galaxies. Their emission lines can provide accurate line-of-sight velocities with a modest investment of telescope time. Also abundances from both HII regions and PNe allow us to derive an approximate enrichment history for a galaxy from intermediate ages to the present day, complementing photometric or spectroscopic metallicity information derived from old red giants. We developed a method to select PNe candidates in the SDSS data and applied it to the entire M31 SDSS data set. The spectra of about 90 selected candidates have been observed with the 2.2m telescope at Calar Alto. The observations show that our method has a selection rate efficiency of about 85 report the discovery of two PNe with projected locations in the center of Andromeda NE, a very low surface brightness giant stellar structure in the outer halo of M31. These two PNe are located at projected distances of \~48 Kpc and \~41 Kpc from the center of M31 and are the most distant PNe in M31 found up to now. We have also discovered one more distant PN at the SW part of M31 with a projected distance of \~37.5 Kpc from the center.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.