Red Giant Branch Stars as Probes of Stellar Populations I: 2MASS Calibration and Application to 2MASS GC01
Red Giant Branch Stars as Probes of Stellar Populations I: 2MASS Calibration and Application to 2MASS GC01
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红巨星分支星作为恒星族群的探测器 I：2MASS 校准及其在 2MASS GC01 中的应用
DOI：
10.1051/0004-6361:20020748
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
J. Borissova
中科院分区：
文献类型：
--
作者：
V. Ivanov;J. Borissova
红巨星分支(以下简称RGB)的近红外行为作为丰度的函数，用两微米全天巡天光度计史无前例地检测了27个银河系球状星系团的近红外行为。我们提出了一种新的简化分析，涉及RGB斜率拟合的零点，并推导了RGB斜率、零点和尖端的校准。零点的弱金属丰度敏感性导致了用于获得已分辨恒星系统中丰度分布的“扇形”图，并使估计变红。最后，我们将新的定标应用于最近发现的银河系球状星系团2MASS GC01，得到[Fe/H]_H96=-1.19+/-0.38 mag。不确定性主要是由严重的前景污染造成的。我们估计A_V=21.07+/-2.20 MAG。
The near-infrared behavior of the red giant branch (RGB hereafter) as a function of abundance is examined with an unprecedented large sample of 27 Galactic globular clusters with Two Micron All Sky Survey photometry. We propose a new simplified analyses, involving the zero point of the RGB slope fit, and derive calibrations for the RGB slope, zero point, and tip. The weak metallicity sensitivity of the zero point leads to a ``fan''-like diagram for obtaining the abundance distributions in resolved stellar systems, and reddening estimates. Finally, we apply the new calibrations to the recently discovered Galactic globular cluster 2MASS GC01, to derive [Fe/H]_H96=-1.19+/-0.38 mag. The uncertainty is dominated by the severe foreground contamination. We estimate an extinction of A_V=21.07+/-2.20 mag toward the cluster.