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arXiv 1912.08151astro-ph.GA
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从MUSE光谱的自洽模拟看银河系中恒星的恒星星族和星爆的物理性质

Stellar populations and physical properties of starbursts in the Antennae galaxy from self-consistent modelling of MUSE spectra

M. L. P. Gunawardhana, J. Brinchmann, P. M. Weilbacher, P. Norberg, A. Monreal-Ibero, T. Nanayakkara, M. den Brok, L. Boogaard, W. Kollatschny

摘要:

我们已经模拟了恒星和星云的连续和发射线强度比的大规模恒星星族在银河系使用高分辨率和自洽图书馆的模型HII地区周围的中央集群的老化恒星。模型库是使用恒星星族合成代码Starburst 99和光电离模型Cloudy构建的。Geneva和PARSEC恒星演化模型被插入Starburst 99,以便在两个模型之间进行比较。使用光谱拟合的方法,允许在恒星和星云连续谱的光谱特征(如沃尔夫-拉叶功能,Paschen跳),和发射线诊断,以约束模型,我们适用于图书馆的高分辨率MUSE光谱的恒星爆发地区的银河系。通过这种方法,我们能够模拟沃尔夫-拉叶星的连续辐射,并通过利用全光谱提取恒星和气体的金属丰度、年龄、电子温度和星爆密度。通过对NGC 4038星系的应用,我们发现:(1)NGC 4038星系中的星暴具有太阳附近的恒星和气体金属丰度的特征;(2)NGC 4038西环星暴中的恒星形成气体似乎比其他星系中的恒星形成气体稍富,(3)最年轻的恒星爆发出现在重叠区和部分西环上,尽管相比之下,西环区的恒星形成阶段似乎比重叠区稍晚,(4)用Geneva和Parsec模型拟合得到的结果基本一致。

英文摘要:

We have modelled the stellar and nebular continua and emission-line intensity ratios of massive stellar populations in the Antennae galaxy using high resolution and self-consistent libraries of model HII regions around central clusters of aging stars. The model libraries are constructed using the stellar population synthesis code, Starburst99, and photoionisation model, Cloudy. The Geneva and PARSEC stellar evolutionary models are plugged into Starburst99 to allow comparison between the two models. Using a spectrum-fitting methodology that allows the spectral features in the stellar and nebular continua (e.g. Wolf-Rayet features, Paschen jump), and emission-line diagnostics to constrain the models, we apply the libraries to the high-resolution MUSE spectra of the starbursting regions in the Antennae galaxy. Through this approach, we were able to model the continuum emission from Wolf-Rayet stars and extract stellar and gas metallicities, ages, electron temperatures and densities of starbursts by exploiting the full spectrum. From the application to the Antennae galaxy, we find that (1) the starbursts in the Antennae galaxy are characterised by stellar and gas metallicities of around solar, (2) the star-forming gas in starbursts in the Western loop of NGC 4038 appear to be more enriched, albeit slightly, than the rest of galaxy, (3) the youngest starbursts are found across the overlap region and over parts of the western-loop, though in comparison, the regions in the western-loop appear to be at a slightly later stage in star-formation than the overlap region, and (4) the results obtained from fitting the Geneva and Parsec models are largely consistent.

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