沃尔夫-拉叶星系中的大质量恒星形成。IV：颜色、化学成分分析和金属度-光度关系
Massive star formation in Wolf-Rayet galaxies. IV: Colours, chemical composition analysis and metallicity-luminosity relations
摘要：
我们对一个星暴星系样本进行了多波长分析，这些样本显示存在大量非常年轻的大质量（WR）恒星。在这里，我们提出了全球分析的光度和化学性质。我们比较光学/近红外颜色和物理性质（红化系数，等效宽度的发射和潜在的吸收线，电离度，电子密度和电子温度）和化学性质与以前的观测和星系演化模型。注意到它们的绝对B星等，其中许多不是矮星系，但它们应该处于静止阶段。我们发现，C（Hb）和Wabs的增加与金属丰度。我们检测到一个高的N/O比的对象显示出强大的WR功能。WR星的喷出物可能是这些星系中N富集的来源。我们比较了直接方法和经验校准方法得到的丰度，发现（i）Pilyugin方法是最合适的经验校准方法，（ii）Pettini和Pagel（2004）提供的氧丰度和N2或O3 N2参数之间的关系对于12+log（O/H）>8.0的对象给出了可接受的结果，和（iii）基于光电离模型的经验校准提供的结果系统地比从直接方法得到的值高0.2- 0.3dex。O和N丰度和N/O比值与光学/近红外光度有关;色散是恒星形成历史差异的结果。颜色较红的银河系往往有较高的氧和氮丰度。我们的详细分析对于理解具有强烈星暴的星系的性质，以及了解它们的恒星形成历史及其与环境的关系至关重要。
英文摘要：
(Abridged) We performed a multiwavelength analysis of a sample of starburst galaxies that show the presence of a substantial population of very young massive (WR) stars. Here we present the global analysis of the derived photometric and chemical properties. We compare optical/NIR colours and the physical properties (reddening coefficient, equivalent widths of the emission and underlying absorption lines, ionization degree, electron density, and electron temperature) and chemical properties with previous observations and galaxy evolution models. Attending to their absolute B-magnitude many of them are not dwarf galaxies, but they should be during their quiescent phase. We found that both C(Hb) and Wabs increase with increasing metallicity. We detected a high N/O ratio in objects showing strong WR features. The ejecta of the WR stars may be the origin of the N enrichment in these galaxies. We compared the abundances provided by the direct method with those obtained using empirical calibrations, finding that (i) the Pilyugin method is the best suitable empirical calibration, (ii) the relations between the oxygen abundance and the N2 or the O3N2 parameters provided by Pettini & Pagel (2004) give acceptable results for objects with 12+log(O/H)>8.0, and (iii) the results provided by empirical calibrations based on photoionization models are systematically 0.2-0.3 dex higher than the values derived from the direct method. The O and N abundances and the N/O ratios are related to the optical/NIR luminosity; the dispersion is consequence of the differences in the star-formation histories. Galaxies with redder colours tend to have higher oxygen and nitrogen abundances. Our detailed analysis is fundamental to understand the nature of galaxies showing strong starbursts, as well as to know their star formation history and the relationships with the environment.
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