The Milky Way Tomography with SDSS: II. Stellar Metallicity

Understand

Using effective temperature and metallicity derived from SDSS spectra for ~60,000 F and G type main sequence stars (0.2<g-r<0.6), we develop polynomial models for estimating these parameters from the SDSS u-g and g-r colors.

• We apply this method to SDSS photometric data for about 2 million F/G stars and measure the unbiased metallicity distribution for a complete volume-limited sample of stars at distances between 500 pc and 8 kpc.
• The metallicity distribution can be exquisitely modeled using two components with a spatially varying number ratio, that correspond to disk and halo.
• The two components also possess the kinematics expected for disk and halo stars.