Unveiling Galaxy Formation and Cosmic StarFormation History with Dusty Spectrum Energy Distribution Diagnostics

利用恒星爆发演化的光谱能量分布模型，分析了30个亚毫米星系的光谱能量分布，其中包括厄洛斯星系和伽玛暴的宿主星系。根据观测到的紫外亚毫米波SED，我们预测了亚毫米级星系的今天的颜色和星等。然后将它们与椭圆星系的颜色和大小-星等关系进行比较。利用顶重的IMF，发现亚毫米星系的现今颜色和星等与椭圆星系的颜色-星等关系是一致的。我们发现，亚毫米星系的现今平均星等与$L^A*$椭圆星系的平均星等相当。较小质量的亚毫米星系的有效半径与观测到的椭圆星系的有效半径是一致的，而质量较小的亚毫米星系比光度相近的椭圆星系小一个数量级。这表明，大质量亚毫米星系由多个恒星爆发区组成。亚毫米星系中的星爆区被发现是自我调节的，即超新星的反馈与星爆区的自引力几乎是平衡的。在这样的系统中，如何停止恒星的形成取决于暗物质晕的大尺度引力势，而不是星暴本身的性质。这可能是导致椭圆星系颜色-星等关系的重要原因。

We analyse the spectral energy distributions (SEDs) of 30 submm galaxies, including EROs and host galaxies of GRBs, by using an evolutionary SED model of starbursts. From the observed UV-submm SEDs, we predict the present-day colours and magnitudes of submm galaxies. And then compare them with the colour- and size-magnitude relation of elliptical galaxies. With the top-heavy IMF, the present-day colours and magnitudes of submm galaxies are found to be consistent with the colour-magnitude relation of elliptical galaxies. We find that the mean present-day magnitude of submm galaxies corresponds to that of $L^A*$ elliptical galaxies. The derived effective radii of less massive submm galaxies are consistent with the observed effective radius of elliptical galaxies, while massive submm galaxies are an order of magnitude smaller than elliptical galaxies with similar luminosity. This suggests that massive submm galaxies consist of multiple starburst regions. Starburst regions in submm galaxies are found to be self-regulated ; i.e.feedback due to supernovae is nearly balanced with the self-gravity of starburst regions. In such systems, how to cease the star formation depends on the large scale gravitational potential by the dark matter halo, rather than the properties of starburst itself. This may be important to cause the colour-magnitude relation of elliptical galaxies.