Spectroscopy of red giants of the Sagittarius dwarf galaxy

The photometric study of the Sagittarius dwarf galaxy by Marconi et al. (1998) has suggested the presence of a spread in metallicity (-0.7 less than or equal to [Fe/H] less than or equal to -1.6), which may result from different bursts of star formation. We present the results from a Multi Object Slit spectroscopy program carried out at the NTT with the aim to determine spectroscopic abundances of Sagittarius giants selected from the CCD photometry. From our intermediate resolution (Rsimilar to1500) spectra, radial velocities are determined to confirm the membership and metallicities are derived by using spectral synthesis codes for stars down to V similar to 18, i.e. below the RGB clump. Out of 57 observed stars, 23 have a radial velocity consistent with Sagittarius membership; here we present results for 8 of these. No star with [Fe/H]< -1.0 is found, three stars are found to be metal-rich.