Spectroscopic study of globular clusters in the halo of M31 with the Xinglong 2.16 m telescope II: dynamics, metallicity and age
文献类型：期刊论文
| 作者 | Fan, Zhou1 ; Huang, Ya-Fang1,2; Li, Jin-Zeng1; Zhou, Xu1; Ma, Jun1; Zhao, Yong-Heng1
|
| 刊名 | RESEARCH IN ASTRONOMY AND ASTROPHYSICS
 |
| 出版日期 | 2012-07-01 |
| 卷号 | 12期号:7页码:829-844 |
| 关键词 | galaxies: individual (M31) galaxies: star clusters globular clusters: general star clusters: general |
| 英文摘要 | In Paper I, we performed spectroscopic observations on 11 confirmed globular clusters (GCs) in M31 with the Xing long 2.16 m telescope. We mainly focused on the fitting method and the metallicity gradient for the M31 GC sample. Here, we analyze and further discuss the dynamics, metallicity and age, and their distributions, as well as the relationships between these parameters. In our work, eight more confirmed GCs in the halo of M31 were observed, most of which lack previous spectroscopic information. These star clusters are located far from the galactic center at a projected radius of similar to 14 to similar to 117 kpc, which is more spatially extended than that in the previous work. Firstly, we measured the Lick absorption-line indices and the radial velocities. Then the ages and metallicity values of [Fe/H] and [alpha/Fe] were fitted by comparing the observed spectral feature indices and the Single Stellar Population model of Thomas et al. in the Cassisi and Padova stellar evolutionary tracks, respectively. Our results show that most of the star clusters in our sample are older than 10 Gyr except B290, which is similar to 5.5 Gyr, and most of them are metal-poor with metallicity [Fe/H] < -1, suggesting that these clusters were born at the early stage of the galaxy's formation. We find that the metallicity gradient for the outer halo clusters with r(p) > 25 kpc may have an insignificant slope of -0.005 +/- 0.005 dex kpc(-1) and if the outliers G001 and H11 are excluded, the slope does not change significantly, with a value of -0.002 +/- 0.003 dex kpc(-1). We also find that the metallicity is not a function of age for the GCs with age < 7 Gyr, but for the old GCs with age > 7 Gyr, there seems to be a trend that the older ones have lower metallicity. Additionally, we plot metallicity distributions with the largest sample of M31 GCs so far and show the bimodality is not significant, and the number of metal-poor and metal-rich groups becomes comparable. The spatial distributions show that the metal-rich group is more centrally concentrated but the metal-poor group occupies a more extended halo. In addition, the young population is centrally concentrated but the old population is more spatially extended towards the outer halo. |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000306892600011 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/6256]  |
| 专题 | 国家天文台_光学天文研究部 |
| 作者单位 | 1.Chinese Acad Sci, Natl Astron Observ, Key Lab Opt Astron, Beijing 100012, Peoples R China 2.Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China |
| 推荐引用方式 GB/T 7714 | Fan, Zhou,Huang, Ya-Fang,Li, Jin-Zeng,et al. Spectroscopic study of globular clusters in the halo of M31 with the Xinglong 2.16 m telescope II: dynamics, metallicity and age[J]. RESEARCH IN ASTRONOMY AND ASTROPHYSICS,2012,12(7):829-844. |
| APA | Fan, Zhou,Huang, Ya-Fang,Li, Jin-Zeng,Zhou, Xu,Ma, Jun,&Zhao, Yong-Heng.(2012).Spectroscopic study of globular clusters in the halo of M31 with the Xinglong 2.16 m telescope II: dynamics, metallicity and age.RESEARCH IN ASTRONOMY AND ASTROPHYSICS,12(7),829-844. |
| MLA | Fan, Zhou,et al."Spectroscopic study of globular clusters in the halo of M31 with the Xinglong 2.16 m telescope II: dynamics, metallicity and age".RESEARCH IN ASTRONOMY AND ASTROPHYSICS 12.7(2012):829-844. |
入库方式： OAI收割
来源：国家天文台
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。