Photometric Metallicity Calibration with SDSS and SCUSS and its Application to distant stars in the South Galactic Cap

Abstract

Based on SDSS g, r and SCUSS (South Galactic Cap of u-band Sky Survey) $u$ photometry, we develop a photometric calibration for estimating the stellar metallicity from $u-g$ and $g-r$ colors by using the SDSS spectra of 32,542 F- and G-type main sequence stars, which cover almost $3700$ deg${}^2$ in the south Galactic cap. The rms scatter of the photometric metallicity residuals relative to spectrum-based metallicity is $0.14$ dex when $g-r<0.4$, and $0.16$ dex when $g-r>0.4$. Due to the deeper and more accurate magnitude of SCUSS $u$ band, the estimate can be used up to the faint magnitude of $g=21$. This application range of photometric metallicity calibration is wide enough so that it can be used to study metallicity distribution of distant stars. In this study, we select the Sagittarius (Sgr) stream and its neighboring field halo stars in south Galactic cap to study their metallicity distribution. We find that the Sgr stream at the cylindrical Galactocentric coordinate of $R\sim 19$ kpc, $\left|z\right|\sim 14$ kpc exhibits a relative rich metallicity distribution, and the neighboring field halo stars in our studied fields can be modeled by two-Gaussian model, with peaks respectively at [Fe/H]$=-1.9$ and [Fe/H]$=-1.5$.

8 pages, 7 figures, Accepted for publication in MNRAS

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Cited by in corpus (10)

• A Blueprint for the Milky Way's Stellar Populations: The Power of Large Photometric and Astrometric Surveys
• South Galactic Cap u-band Sky Survey (SCUSS): Data Release
• Asymmetric Mean Metallicity Distribution of the Milky Way's Disk
• Two Populations of Carbon-Enhanced Metal-Poor Stars in the Disk System of the Milky Way
• Element abundance analysis of the metal-rich stellar halo and high-velocitythick disk in the galaxy
• Existence of the Metal-Rich Stellar Halo and High-velocity Thick Disk in the Galaxy
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• A Monte-Carlo Method for Estimating Stellar Photometric Metallicity Distributions
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• A Monte-Carlo Method for Making SDSS $u$-Band Magnitude more accurate