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arXiv 1505.04799astro-ph.SRastro-ph.GA
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哈伯狼蛛宝藏计划:解开狼蛛的网。II。剑鱼座30星暴星团NGC 2070的光学和近红外恒星形成历史

Hubble Tarantula Treasury Project: Unraveling Tarantula's Web. II. Optical and Near Infrared Star Formation History of the Starburst Cluster NGC 2070 in 30 Doradus

M. Cignoni, E. Sabbi, R. P. van der Marel, M. Tosi, D. Zaritsky, J. Anderson, D. J. Lennon, A. Aloisi, G. de Marchi, D. A. Gouliermis, E. K. Grebel, L. J. Smith, P. Zeidler

摘要:

我们提出了一个研究最近的恒星形成的30剑鱼座的大麦云(LMC)使用全色成像调查哈勃狼蛛国库项目(HTTP)。在本文中,我们集中在20秒差距内的大质量电离星系团30剑鱼座,NGC 2070的中心的恒星。我们通过比较深光学和近红外色星等图(CMD)与最新PARSEC模型生成的最先进的合成CMD来恢复恒星形成历史,其中包括从主序前到主序后的所有恒星相位。这是我们在这一领域首次能够同时使用中低质量恒星测量恒星形成。我们的研究结果表明,NGC 2070经历了一个长期的活动。特别是,我们发现该地区的恒星形成:i)超过了大约2000万年前的平均LMC速率; ii)在大约700万年前急剧加速; iii)在1- 300万年前达到峰值。我们没有发现显着偏离Kroupa初始质量函数下降到0.5 Msun。平均内部红化E(B-V)在0.3 ~ 0.4 mag.

英文摘要:

We present a study of the recent star formation of 30 Doradus in the Large Magellanic Cloud (LMC) using the panchromatic imaging survey Hubble Tarantula Treasury Project (HTTP). In this paper we focus on the stars within 20 pc of the center of the massive ionizing cluster of 30 Doradus, NGC 2070. We recovered the star formation history by comparing deep optical and NIR color-magnitude diagrams (CMDs) with state-of-the-art synthetic CMDs generated with the latest PARSEC models, which include all stellar phases from pre-main sequence to post- main sequence. For the first time in this region we are able to measure the star formation using intermediate and low mass stars simultaneously. Our results suggest that NGC2070 experienced a prolonged activity. In particular, we find that the star formation in the region: i) exceeded the average LMC rate ~ 20 Myr ago; ii) accelerated dramatically ~ 7 Myr ago; and iii) reached a peak value 1-3 Myr ago. We did not find significant deviations from a Kroupa initial mass function down to 0.5 Msun. The average internal reddening E(B-V) is found to be between 0.3 and 0.4 mag.

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