Abstract details

We present the Star Formation History (SFH) of Phoenix dwarf galaxy using IAC-pop algorithm. IAC-pop is a code designed to solve the SFH of a complex stellar population system from the analysis of the color-magnitude diagram (CMD). The application of IAC-POP to HST observations of Phoenix dwarf galaxy using three different stellar evolution libraries (Bertelli et al. 1994, Pietrifernni et al. 2004, and Girardi et al. 2000), shows that the galaxy has a population as young as 1 Gyr. Intermediate-age population has been also detected, although the estimate of its relative importance depends on the used library. In all the cases, a metallicity increasing with time has been observed. Theses results militates against the halo-disk scenario for the galaxy formation, but is favourable to the shrinking scenario where the star formation regions of the galaxy shrink with the time.