The kinematics and chemistry of the Sagittarius streams

We selected red horizontal-branch stars along the streams of the Sagittarius dwarf galaxy (Sgr) from sdss DR7 spectroscopic data using a theoretical model. We investigate the metallicity distribution of stars in the Sgr streams. The metallicity gradient is (-1.8 +/- 0.3) × 10^⊃3 dex deg^-1 in the first wrap of the trailing arm and (-1.5 +/- 0.4) × 10^-3 dex deg^-1 in the first wrap of the leading arm.