Journal Article

Correlations between the Intrinsic Colors and Spectroscopic Metallicities of M31 Globular Clusters

Jiang, Zhaoji, Ma, Jun, Fan, Zhou, Zhou, Xu

2010

Overview

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 ugrizK u g r i z K colors. The BATC colors were derived from the archival images of 13 filters (from c c to p p ) taken by the Beijing-Arizona-Taiwan-Connecticut Multicolor Sky Survey with a60/90 cm 60 / 90     cm 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 ( r r ) of 23 colors r > 0.7 r > 0.7 . For the colors(f - k)0 ( f - k ) 0 ,(f - o)0 ( f - o ) 0 , and(h - k)0 ( h - k ) 0 , the correlation coefficients are r > 0.8 r > 0.8 . Meanwhile, we also note that the correlation coefficients approach zero for(g - h)0 ( g - h ) 0 ,(k - m)0 ( k - m ) 0 ,(k - n)0 ( k - n ) 0 , and(m - n)0 ( m - n ) 0 , which are likely to be independent of metallicity. Similarity, we fitted the correlations of metallicity and ugrizK u g r i z K colors for 127 old confirmed GCs. The result indicates that all these colors are metal-sensitive ( r > 0.7 r > 0.7 ), and(u - K)0 ( u - K ) 0 is the most metal-sensitive color. Our work provides a simple way to estimate the metallicity from colors.

• Publisher: University of Chicago Press
• Subject: Andromeda Galaxy / Astronomical magnitude / Astronomical photometry / Astronomy / Cataloging / Colors / Correlation coefficients / Earth, ocean, space / Exact sciences and technology / Globular star clusters / Metal abundance / Milky Way Galaxy / Spectroscopy