2010PASP..122..636F

We present the correlations between the spectroscopic metallicities and 93 different intrinsic colors of M31 globular clusters, including 78 Beijing-Arizona-Taiwan-Connecticut (BATC) Multicolor Sky Survey colors and 15 SDSS and near-infrared colors. The BATC colors were derived from the archival images of 13 filters (from to) taken by the Beijing-Arizona-Taiwan-Connecticut Multicolor Sky Survey with a f/3 Schmidt telescope. The spectroscopic metallicities adopted in our work were from literature. We fitted the correlations of 78 different BATC colors and the metallicities for 123 old confirmed globular clusters, and the result implies that correlation coefficients of 23 colors . For the colors,, and, the correlation coefficients are. Meanwhile, we also note that the correlation coefficients approach zero for,,, and , which are likely to be independent of metallicity. Similarity, we fitted the correlations of metallicity and colors for 127 old confirmed GCs. The result indicates that all these colors are metal-sensitive , and is the most metal-sensitive color. Our work provides a simple way to estimate the metallicity from colors.