天文学进展2017，Vol.35Issue(2)：220-243,24.DOI:10.3969/j.issn.1000-8349.2017.02.05
中红外波段星系电离特性研究
Study of the Photoionization Properties of Galaxies in Mid-infrared
摘要
Abstract
The source of high ionization emission line [O IV](25.9 μm) is still not clear. The preliminary analysis in Hao et al.(2009) found that when the [Ne III]/[Ne II] ratio given by the models is comparable to observation, the [O IV]/[S III] ratio given by the models are four order of magnitudes lower than the observed value. In this study, we analyze the ratios of mid-infrared emission lines like [O IV]/[S III], [S IV]/[S III], [Ne III]/[Ne II] and their system-atic trend with different changing parameters, by combining the observation data in Hao et al.(2009) with the updated photoionization models in the ITERA package. Through the comparison between the observation and models, we find that the two-branch configuration in the mid-infrared diagnostic diagram [O IV]/[S III]对[S IV]/[S III]can be matched by the AGN and starburst models well separately. We find that the strength of [O IV] emission in these starburst models is closely related to the relative photon flux with energy larger than 4 Ryd in the ionization spectra. The contribution from Wolf-Rayet stars alone can provide enough [O IV] emission to explain the observation. As for the [O IV]/[S III]对[Ne III]/[Ne II] diagram, the models can not explain the observation well, especially for the starburst branch: when the [O IV]/[S III] value in the models is comparable to the observation, the [Ne III]/[Ne II] in mod-els are still higher than that from observation. Combining with the fact that models match observation well in [O IV]/[S III]对[S IV]/[S III] diagram, we think the reason why starburst models can not explain observation could be that the models predict higher [Ne III]/[Ne II], but not that they can not generate enough [O IV] emission. We find that if we only con-sider that emission comes only from a zone with uniform density and ionization parameter, [Ne III]/[Ne II] correlates closely with the spectrum index in the ionization spectrum ranging from 21.6 eV to 41.0 eV.关键词
光致电离/星暴星系/BCD/活动星系核/极亮红外星系Key words
photoionization/Starburts/BCD/Active Galactic Nuclei/ULIRG分类
天文与地球科学引用本文复制引用
刘伟哲,郝蕾..中红外波段星系电离特性研究[J].天文学进展,2017,35(2):220-243,24.基金项目
国家自然科学基金(11473305) （11473305）
中国科学院战略性先导专项B 类(XDB09030200) （XDB09030200）
