Talk abstract details

The Panchromatic Hubble Andromeda Treasury (PHAT) is a Hubble Space Telescope Multi-cycle program to map roughly a third of M31’s star forming disk, using 6 filters covering from the ultraviolet through the near infrared. We have cross-matched the Merrett et al. (2006) catalog of M31 PNe with the first PHAT data obtained in cycle 18. The most interesting results so far regard the UV-optical photometry of PNe in the M31 bulge and inner disk. For all objects with F475W<22, we find a very close relationship between the [OIII]5007 and F475W magnitudes. The PNe stand out clearly in well-defined regions of color-color plots, especially those involving the F275W, F336W and F475W filters. A substantial fraction of the objects with a blue F475W-F814W color in PHAT catalogs are PNe. We discuss the observed trends in the light of synthetic models for the evolution of PNe (Marigo et al. 2001), and considering the properties of the underlying stellar populations as derived from PHAT data.