Infrared Study of Mass Distribution in Extra Galactiv Halo

到目前为止，对于星系中引力质量的来源还没有明确和一致的解释。可见的恒星质量不足以解释星系外围所谓的平旋转速度。在这项观测研究中，我们试图测量外星系晕区的表面亮度分布，以检验晕中微弱的低质量恒星的贡献。我们利用安装在夏威夷莫纳克亚的犹他大学望远镜上的独特仪器OHS，在一个名为“UGC7617”的边缘螺旋星系的延伸晕的微弱发射的可见和近红外波段获得了观测结果。通过这次观测，我们在光晕区域发现了一种非常红色的漫射成分。根据发射分量的光谱能量分布和空间分布，并通过构建星系模型，推断出探测到的具有代表性的低质量恒星类型，从而估算出恒星对光晕总质量的贡献。

There have so far not been definite and consistent interpretations about the source of gravitational mass in a galaxy. the visible stellar mass is not sufficient to explain the so-called flat rotation velocity in the outskirt of galaxies. In this observational research, we attempt to measure the surface brightness distribution of halo region of an external galaxy to examine the contribution of faint low-mass stars in the halo.We have oabtained observational results in both the visible and near-infrared bands of faint emission of the extended halo in one of edge-on spiral galaxies called 'UGC7617', using our unique instrument called OHS mounted on the UH telescope on Mauna Kea, Hawaii. With this observations, we have found a diffuse emission component of a very red color in the halo region. Based on the spectral energy distribution as well as spatial distribution of the emission component, and also by constructing a model of the galaxy, we have inferred the representative types of low-mass stars detected and thus estimated the stellar contribution to the total mass of the halo.