The chemical content of nearby galaxies: NGC 147

Abstract

The dwarf spheroidal galaxy NGC 147 is one of the companions of the Andromeda galaxy. In this contribution we show the first spectroscopic results for the PN population of NGC 147, obtained from the GEMINI Multi-Object Spectrograph (GMOS) in December 2005. We present our results on the physical and chemical properties of the planetary nebulae. At variance with the behaviour of the old stellar population of the galaxy, the metallicity of PNe is roughly constant through the galaxy. Moreover, if the $\pm$ 0.06 dex of the [Fe/H] to [O/H] conversion is considered, there is no difference between the RGB and the PNe metallicities. We also show that the PNe in NGC 147 are 1 to 10 Gyr-old. Therefore, these results suggest that NGC 147 had no significant enrichment for a long period of time.