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arXiv 1402.0075astro-ph.COastro-ph.GA
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星系光度函数和它的宇宙学演化:检验一个依赖于星系尺度尘埃不透明度的新反馈模型

Galaxy luminosity function and its cosmological evolution: Testing a new feedback model depending on galaxy-scale dust opacity

Ryu Makiya, Tomonori Totani, Masakazu A. R. Kobayashi, Masahiro Nagashima, Tsutomu T. Takeuchi

摘要:

我们提出了一个新版本的宇宙学星系形成的半解析模型,纳入了恒星形成的法律与反馈依赖于星系尺度的平均尘埃不透明度和金属丰度,最近在附近星系的恒星形成的观测和理论考虑的动机。这个新的模型被用来研究这种反馈对塑造星系光度函数及其演化的影响。恒星形成活动显着抑制矮星系的新的反馈效应,和本地光度函数的暗端斜率可以再现与一个合理的强度的超新星反馈,这是在以前的模型,需要一个相当极端的强度的超新星反馈。我们的模型也可以再现早期出现的大质量星系表现在高红移K波段光度函数的亮端。虽然之前的一些模型也成功地重现了这一点,但它们假设恒星形成定律取决于星系尺度的动力学时间,这并不被观测所支持。我们认为,依赖于尘埃不透明度(或金属柱密度)的反馈是必不可少的,而不是简单地依赖于气柱密度,得到这些结果。

英文摘要:

We present a new version of a semi-analytic model of cosmological galaxy formation, incorporating a star formation law with a feedback depending on the galaxy-scale mean dust opacity and metallicity, motivated by recent observations of star formation in nearby galaxies and theoretical considerations. This new model is used to investigate the effect of such a feedback on shaping the galaxy luminosity function and its evolution. Star formation activity is significantly suppressed in dwarf galaxies by the new feedback effect, and the faint-end slope of local luminosity functions can be reproduced with a reasonable strength of supernova feedback, which is in contrast to the previous models that require a rather extreme strength of supernova feedback. Our model can also reproduce the early appearance of massive galaxies manifested in the bright-end of high redshift K-band luminosity functions. Though some of the previous models also succeeded in reproducing this, they assumed a star formation law depending on the galaxy-scale dynamical time, which is not supported by observations. We argue that the feedback depending on dust opacity (or metal column density) is essential, rather than that simply depending on gas column density, to get these results.

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