标题： 矮星系团不规则星系 IC10 的物理条件。 一- 扩散电离气体 显示英文标题

标题： Physical Conditions in the Dwarf Local Group Irregular Galaxy IC10. I- Diffuse Ionized Gas

摘要： 利用长缝光谱对本星系群矮小的不规则星系IC 10主体中的星际介质物理条件进行了详细分析。展示了激发态图、H$\alpha$通量，[NII]/H$\alpha$和[SII]/H$\alpha$的分布图。研究了星系内的弥散电离气体。我们发现光谱特征与螺旋星系的不同：[NII]/H$\alpha$和[SII]/H$\alpha$的比值不像在螺旋星系中那么大，但激发态却大得多。这些值，尤其是大的激发态，可以通过提出额外的电离源来解释。研究了不同的源，但除了从星系中的HII区域泄漏的光子以及由该星系中存在的WR恒星提供的电离的组合外，现有的任何模型都无法真正拟合。除了星系西侧的一小部分外，无需冲击波来解释线强度比。 显示英文摘要

摘要： A detailed analysis on the physical conditions of the Interstellar Medium in the main body of the Local Group dwarf irregular galaxy IC 10 is carried out using long-slit spectroscopy. Maps of the excitation, the H$\alpha$ flux, [NII]/H$\alpha$ and [SII]/H$\alpha$ are presented. The Diffuse Ionized Gas inside the galaxy is studied. We found that the spectral characteristics are not similar to those for spiral galaxies: the values of the ratios [NII]/H$\alpha$ and [SII]/H$\alpha$ are not as large as in spiral galaxies but the excitation is much larger. These values, especially the large excitation, can be explained by proposing an extra source of ionization. Different sources are studied but any of the models at hand could be really fitted except a combination of photons leaking from the HII regions in addition to the ionization provided by the WR stars present in this galaxy. Shocks are not needed for explaining the line intensity ratios except in a small part in the west side of the galaxy.