The VMC survey - XVI. Spatial variation of the cluster formation activity in the innermost regions of the Large Magellanic Cloud
The VMC survey - XVI. Spatial variation of the cluster formation activity in the innermost regions of the Large Magellanic Cloud
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VMC 调查 - XVI。
DOI：
10.1093/mnras/stv2054
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发表时间：
2015
影响因子：
4.8
通讯作者：
For Bi-Qing
中科院分区：
文献类型：
--
作者：
Piatti Andres E.;de Grijs Richard;Ripepi Vincenzo;Ivanov Valentin D.;Cioni Maria-Rosa L.;Marconi Marcella;Rubele Stefano;Bekki Kenji;For Bi-Qing
我们给出了大麦哲伦星云(LMC)中星团的YJK光度测量结果，这些星团分布在银河系棒的中央部分和30个剑鱼座区域。我们分析了313个星系团的场恒星去污染色等图，以估计它们的红化值和年龄。团簇受E(B−V)∈[0.2，0.3]∼平均变红的影响，其中平均内部LMC变红相当于LMC 0.1-0.2。覆盖30个剑鱼座的区域包括红化值超过E(B−V)=0.4兆的星系团。我们的集群样本跨越年龄范围7.0TYR LOG (TYR−1)<；9.0，就具有稳健年龄估计的集群数量而言，表示每 每 增加30个TIR，并包括此处感兴趣的LMC区域的统计完整样本。由此得到的星团频率表明，在活动进行之前，LMC条最外层的区域首先经历了增强的星团形成-对数 (Tyr−1)∈[8.5，9.0]，尽管以一种零星的方式到达最内侧区域，对数 (Tyr−1)和lt；7.7。剑鱼座30号区域的星系团频率表明，该地区主要是最近形成的星系团。得出的恒星形成频率表明，在最近的∼100Myr期间，星系团和场-星群体似乎并没有完全演化为完全耦合的系统。
We present results based onYJKsphotometry of star clusters in the Large Magellanic Cloud (LMC), distributed throughout the central part of the galaxy's bar and the 30 Doradus region. We analysed the field-star-decontaminated colour–magnitude diagrams of 313 clusters to estimate their reddening values and ages. The clusters are affected by a mean reddening ofE(B−V) ∈ [0.2, 0.3] mag, where the average internal LMC reddening amounts to ∼0.1–0.2 mag. The region covering 30 Doradus includes clusters with reddening values in excess ofE(B−V) = 0.4 mag. Our cluster sample spans the age range 7.0 ≤ log (tyr−1) < 9.0, represents an increase of 30 per cent in terms of the number of clusters with robust age estimates and comprises a statistically complete sample in the LMC regions of interest here. The resulting cluster frequencies suggest that the outermost regions of the LMC bar first experienced enhanced cluster formation – log (tyr−1) ∈ [8.5, 9.0] – before the activity proceeded, although in a patchy manner, to the innermost regions, for log (tyr−1) < 7.7. Cluster frequencies in the 30 Doradus region show that the area is dominated by very recent cluster formation. The derived star formation frequencies suggest that the cluster and field-star populations do not seem to have fully evolved as fully coupled systems during the last ∼100 Myr.