SCUSS测光金属丰度定标及南银冠人马座星流的金属丰度估计

基于SDSS g,SDSS r和SCUSS u测光数据,利用F/G型主序星的光谱,从u－g和g－r色指数中进行测光金属丰度定标.定标过程中,当g－r<0.4时,测光金属丰度与基于光谱的金属丰度之间的方均根误差为0.14,当g－r>0.4时为0.16.由于SCUSS u更深更精确的星等,能够将测光金属丰度估计的应用范围设置在g<21内.选择南银冠人马座星流来研究金属丰度分布,发现大约在以银心为中心的柱坐标R~19 kpc和|Z|~14 kpc处的人马座星流呈现出比背景晕星更富的金属丰度分布.

Photometric metallicity calibration based on SCUSS and metallicity estimates of Sagittarius stream in south Galactic cap

Based on SDSS g,SDSS r,and SCUSS u photometry, we develop a photometric calibration for estimating the stellar metallicity from u－g and g－r colors by using the spectra of F- and G-type main-sequence stars. 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, we set the application of photometric metallicity estimation in the range of g<21. We select the Sagittarius (Sgr) stream stars in south Galactic cap to study metallicity distribution. We find that the Sgr stream at the cylindrical Galactocentric coordinates of R~19 kpc and |Z|~14 kpc exhibits a more metal-rich distribution than the halo.