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arXiv 1905.09528astro-ph.GA
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用于光学诊断的星暴光电离理论模型的比较

Comparison of Theoretical Starburst Photoionisation Models for Optical Diagnostics

Joshua J. D'Agostino, Lisa J. Kewley, Brent Groves, Nell Byler, Ralph S. Sutherland, David Nicholls, Claus Leitherer, Elizabeth R. Stanway

摘要:

我们研究和比较不同的例子恒星演化合成输入参数用于产生光电离模型网格使用MAPPINGS V建模代码。本研究的目的是(a)探索各种恒星演化合成模型参数对光学强线诊断图中发射线解释的系统性影响,(b)验证能够再现斯隆数字巡天中位于恒星形成区的本星系扩散的参数组合,以及(c)使用光电离模型研究极端贫金属星系的发射。我们探索和比较恒星输入电离光谱(恒星星族合成代码[Starburst99,SLUG,BPASS],恒星演化轨迹,恒星大气,恒星形成的历史,采样的初始质量函数)以及固有的H II区域的参数(金属丰度,电离参数,压力,H II区域的有界性)。我们还进行了比较的光电离代码映射和云。在电离光谱模型参数的变化,我们发现,不同的模型之间的强发射线的比率的差异对于一个给定的输入模型参数是小的,平均约0.1德克斯。使用MAPPINGS和CLOUDY生成的模式之间的发射线比平均相差约0.1 dex。当比较本征H II区参数时,发现发射线比之间存在较大差异。我们发现,低金属量的星系更好地解释了密度有界的H II区域和更高的压力更好地包括在高红移星系的传播。

英文摘要:

We study and compare different examples of stellar evolutionary synthesis input parameters used to produce photoionisation model grids using the MAPPINGS V modelling code. The aim of this study is to (a) explore the systematic effects of various stellar evolutionary synthesis model parameters on the interpretation of emission lines in optical strong-line diagnostic diagrams, (b) characterise the combination of parameters able to reproduce the spread of local galaxies located in the star-forming region in the Sloan Digital Sky Survey, and (c) investigate the emission from extremely metal-poor galaxies using photoionisation models. We explore and compare the stellar input ionising spectrum (stellar population synthesis code [Starburst99, SLUG, BPASS], stellar evolutionary tracks, stellar atmospheres, star-formation history, sampling of the initial mass function) as well as parameters intrinsic to the H II region (metallicity, ionisation parameter, pressure, H II region boundedness). We also perform a comparison of the photoionisation codes MAPPINGS and CLOUDY. On the variations in the ionising spectrum model parameters, we find that the differences in strong emission-line ratios between varying models for a given input model parameter are small, on average ~0.1 dex. An average difference of ~0.1 dex in emission-line ratio is also found between models produced with MAPPINGS and CLOUDY. Large differences between the emission-line ratios are found when comparing intrinsic H II region parameters. We find that low-metallicity galaxies are better explained by a density-bounded H II region and higher pressures better encompass the spread of galaxies at high redshift.

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