Intermediate to low-mass stellar content of Westerlund 1
Intermediate to low-mass stellar content of Westerlund 1
复制标题
Westerlund 1 的中到低质量恒星含量
DOI：
10.1051/0004-6361:20077579
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发表时间：
2007
影响因子：
6.5
通讯作者：
S. Goodwin
中科院分区：
文献类型：
--
作者：
W. Brandner;J. Clark;A. Stolte;R. Waters;I. Negueruela;S. Goodwin
我们分析了近红外NTT/SofI观测的星暴集群Westerlund 1，这是银河系中最大的年轻集群之一。通过比较色星等图与理论上的主序星和前主序星演化轨迹，得到了更好的灭绝和距离估计值：AKs = 1.13 ± 0.03等，d = 3.55 ± 0.17千秒差距（DM = 12.75 ± 0.10等）。前主序人口是最好的适合由Palla & Stahler等时线的年龄为320万年，而主序人口是在协议的集群年龄为3至5百万年。的集群的结构参数的分析产生的集群人口的半质量半径增加向较低的质量，表明存在质量分离。这个星团明显是拉长的，质量在10到32 M�之间的恒星离心率为0.20，质量在3到10 M�之间的恒星离心率为0.15。我们推导出质量在3.4到27 M ²之间的恒星质量函数的斜率。在一个距离星系团中心半径为0.75 ~ 1.5 pc的环中，我们得到的斜率为Γ= −1.3。更近一点，韦斯特伦德的质量函数#[
We have analysed near-infrared NTT/SofI observations of the starburst cluster Westerlund 1, which is among the most massive young clusters in the Milky Way. A comparison of colour-magnitude diagrams with theoretical main-sequence and pre-main sequence evolutionary tracks yields improved extinction and distance estimates of AKs = 1.13 ± 0.03 mag and d = 3.55 ± 0.17 kpc (DM = 12.75 ± 0.10 mag). The pre-main sequence population is best fit by a Palla & Stahler isochrone for an age of 3.2 Myr, while the main sequence population is in agreement with a cluster age of 3 to 5 Myr. An analysis of the structural parameters of the cluster yields that the half-mass radius of the cluster population increases towards lower mass, indicative of the presence of mass segregation. The cluster is clearly elongated with an eccentricity of 0.20 for stars with masses between 10 and 32 M� , and 0.15 for stars with masses in the range 3 to 10 M� . We derive the slope of the stellar mass function for stars with masses between 3.4 and 27 M� . In an annulus with radii between 0.75 and 1.5 pc from the cluster centre, we obtain a slope of Γ= −1.3. Closer in, the mass function of Westerlund #[