Global Distribution of Far-ultraviolet Emissions from Highly Ionized Gas in the Milky Way
Global Distribution of Far-ultraviolet Emissions from Highly Ionized Gas in the Milky Way
复制标题
银河系高电离气体远紫外线发射的全球分布
DOI：
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发表时间：
2019
影响因子：
8.7
通讯作者：
M. Sirk
中科院分区：
文献类型：
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作者：
Y. Jo;K. Seon;K. Min;J. Edelstein;W. Han;E. Korpela;M. Sirk
我们提出了高电离气体的两个主要远紫外冷却线，C iv和O vi的全天空图，以研究过渡温度气体的性质。根据消光校正后的C - iv和O - vi谱线强度，我们计算了在碰撞电离平衡中假设等温等离子体的气体温度和过渡温度气体的发射量。整个星系的气体温度大致均匀，为（1.89±0.06）× 105 K。用电子密度标度高度为kpc的盘状模型很好地描述了过渡温度气体的发射测量。过渡温度气体的总质量估计约为。我们还计算了过渡温度气体的体积填充分数，估计为f = 0.26±0.09，其变化范围从内星系的f ~ 0.37到外星系的f ~ 0.18。civ和ovi的空间分布不能用简单的超新星遗迹模型或三相模型来解释。超新星残骸和湍流混合层的共同作用可以解释civ和ovi的强度比，热传导锋模型和高速云模型也与我们的观测结果一致。
We present all-sky maps of two major far-ultraviolet cooling lines, C iv and O vi, of highly ionized gas to investigate the nature of the transition-temperature gas. From the extinction-corrected line intensities of C iv and O vi, we calculated the gas temperature and the emission measure of the transition-temperature gas assuming isothermal plasma in the collisional ionization equilibrium. The gas temperature was found to be more or less uniform throughout the Galaxy with a value of (1.89 ± 0.06) × 105 K. The emission measure of the transition-temperature gas is described well by a disk-like model in which the scale height of the electron density is kpc. The total mass of the transition-temperature gas is estimated to be approximately . We also calculated the volume-filling fraction of the transition-temperature gas, which was estimated to be f = 0.26 ± 0.09, and it varies from f ∼ 0.37 in the inner Galaxy to f ∼ 0.18 in the outer Galaxy. The spatial distribution of C iv and O vi cannot be explained by a simple supernova remnant model or a three-phase model. The combined effects of supernova remnants and turbulent mixing layers can explain the intensity ratio of C iv and O vi. Thermal conduction front models and high-velocity cloud models are also consistent with our observation.