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arXiv 0903.0946astro-ph.GA
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银河系核球的恒星族

Stellar populations in the Galactic bulge

E. Vanhollebeke, M. A. T. Groenewegen, L. Girardi

AI总结:

本研究通过将星系模型TRILEGAL与2MASS、OGLE-II观测数据对比,拟合得到银河系核球的结构参数、恒星年龄与金属丰度分布特征,结果与已有光谱研究结论相符。

摘要:

研究目的:本文旨在研究银河系核球的恒星族特征与金属丰度分布。我们既研究了整体恒星族,也仅利用红团簇星获取了相关信息。研究方法:为探究银河系核球的恒星族特征与金属丰度分布,我们将搭载了Binney等人(1997)提出的核球模型的星系模型TRILEGAL的输出结果,与2MASS和OGLE-II的观测数据进行对比。我们构建了一套最小化流程,以获取匹配不同恒星族与金属丰度分布的最优拟合模型。研究结果:通过TRILEGAL程序我们发现,最符合银河系核球特征的模型参数为:到银心的距离$R_0 = 8.7\boldsymbol{+0.57 \brace -0.43}$ kpc,核球棒的长轴比例$1:η:ζ= 1 : 0.68\boldsymbol{+0.05 \brace -0.19} : 0.31\boldsymbol{+0.06 \brace -0.04}$,日心连线与核球棒的夹角$ϕ= 15°\boldsymbol{+13.3 \brace -12.7}$。基于这些参数,最优模型对应80亿年的恒星形成暴,不过该模型与年龄为90亿年、100亿年的模型几乎无法区分。所得金属丰度分布与文献中基于光谱结果得到的金属丰度分布一致。

英文摘要:

AIMS:The aim of this paper is to study the characteristics of the stellar populations and the metallicity distribution in the Galactic bulge. We study the entire stellar population, but also retrieve information using only the red clump stars. METHODS: To study the characteristics of the stellar populations and the metallicity distribution in the Galactic bulge, we compared the output of the galaxy model TRILEGAL, which implements the Binney et al. (1997) bulge model, with observations from 2MASS and OGLE-II. A minimisation procedure has been set up to retrieve the best fitting model with different stellar populations and metallicity distributions. RESULTS: Using the TRILEGAL code we find that the best model resembling the characteristics of the Galactic bulge is a model with the distance to the Galactic centre $R_0 = 8.7\pm^{0.57}_{0.43}$ kpc, the major axis ratios of the bar $1:η:ζ= 1 : 0.68\pm_{0.19}^{0.05} : 0.31\pm_{0.04}^{0.06}$, and the angle between the Sun-centre line and the bar $ϕ= 15°\pm_{12.7}^{13.3}$. Using these parameters the best model is found for a burst of 8 Gyr, although it is almost indistinguishable from models with ages of 9 and 10 Gyr. The metallicity distribution found is consistent with metallicity distributions in the literature based on spectroscopic results.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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