我们给出了M31球状星团的光谱金属丰度与93种不同的本征色之间的相关关系，其中包括78种BATC色和15种SDSS色以及近红外ugrizK色。BATC的颜色来源于北京-亚利桑那-台湾-康涅狄格（BATC）多色巡天用60/90 cm f/3施密特望远镜拍摄的13个滤光片（从c到p）的档案图像。本工作中采用的光谱金属丰度来自文献。对123个年龄较大的球状星团的78种不同的BATC颜色与金属丰度的相关性进行了拟合，结果表明23种颜色的相关系数r>0.7。特别地，对于颜色$(f-k)_0$、$(f-o)_0$和$(h-k)_0$，相关系数r>0.8。同时，我们还注意到$(g-h)_0$、$(k-m)_0$、$(k-n)_0$和$(m-n)_0$的相关系数（r）接近于零，这可能与金属丰度无关。相似性，我们拟合了127个老确认GC的金属丰度和ugrizK颜色的相关性。结果表明，这些颜色都具有金属敏感性（r>0.7），其中$(u-K)_0$的金属敏感性最强。我们的工作提供了一个简单的方法来简单地估计金属的颜色。
英文摘要：
We present the correlations between the spectroscopic metallicities and ninety-three different intrinsic colors of M31 globular clusters, including seventy-eight BATC colors and fifteen SDSS and near infrared ugrizK colors. The BATC colors were derived from the archival images of thirteen filters (from c to p), which were taken by Beijing-Arizona-Taiwan-Connecticut (BATC) Multicolor Sky Survey with a 60/90 cm f/3 Schmidt telescope. The spectroscopic metallicities adopted in our work were from literature. We fitted the correlations of seventy-eight different BATC colors and the metallicities for 123 old confirmed globular clusters, and the result implies that correlation coefficients of twenty-three colors r>0.7. Especially, for the colors $(f-k)_0$, $(f-o)_0$, and $(h-k)_0$, the correlation coefficients are r>0.8. Meanwhile, we also note that the correlation coefficients (r) approach zero for $(g-h)_0$, $(k-m)_0$, $(k-n)_0$, and $(m-n)_0$, which are likely to be independent of metallicity. Similarity, we fitted the correlations of metallicity and ugrizK colors for 127 old confirmed GCs. The result indicates that all these colors are metal-sensitive (r>0.7), of which $(u-K)_0$ is the most metal-sensitive color. Our work provides an easy way to simply estimate the metallicity from colors.
Nonlinear Color-Metallicity Relations of Globular Clusters. II. A Test on the Nonlinearity Scenario for Color Bimodality Using the u-band Colors: The Case of M87 (NGC 4486)
Photo-Met: a non-parametric method for estimating stellar metallicity from photometric observations
获得良好信噪比的光谱比光度观测多花了几个数量级的时间。建立在星系的光度红移估计技术的基础上，我们开发并演示了一种非参数光度方法，用于估计银河系恒星的化学成分。我们调查我们的方法使用光谱确定的恒星金属丰度SDSS DR 7的效率。该技术是通用的，因为它不限于某些恒星类型或恒星参数范围，并且可以获得比光谱测量所允许的更大样本的金属丰度和误差估计。我们发现，我们的方法表现良好，特别是对于较亮的恒星和较高的金属丰度，与许多其他技术相比，我们能够可靠地估计预测的金属丰度的误差。
