arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1408.6444astro-ph.GAastro-ph.CO
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重新审视具有中心密度核的暗物质晕的“大到不能倒”问题

Re-examining the Too-Big-To-Fail Problem for Dark Matter Haloes with Central Density Cores

Go Ogiya, Andreas Burkert

摘要:

最近的研究发现,围绕矮球状星系(dSphs)的暗物质(DM)暗晕的密度明显低于宇宙学模拟中银河系大小星系周围最大质量暗晕的密度,即所谓的“太大而不能倒”(TBTF)问题。一个警告以前的工作一直被认为是黑暗的子结构包含在DM晕中心陡峭的密度尖点,即使DM晕的中心密度结构仍在争论中。在这项研究中,我们重新研究了模型的DM密度结构的核心或浅尖点的TBTF问题。我们的分析表明,TBTF问题得到缓解的对数斜率的中心尖点变得更浅。我们发现,TBTF问题是避免的,如果周围dSphs的DM晕的中心尖点比$r^{-0.6}$浅。

英文摘要:

Recent studies found the densities of dark matter (DM) subhaloes which surround nearby dwarf spheroidal galaxies (dSphs) to be significantly lower than those of the most massive subhaloes expected around Milky Way sized galaxies in cosmological simulations, the so called "too-big-to-fail" (TBTF) problem. A caveat of previous work has been that dark substructures were assumed to contain steep density cusps in the center of DM haloes even though the central density structure of DM haloes is still under debate. In this study, we re-examine the TBTF problem for models of DM density structure with cores or shallowed cusps. Our analysis demonstrates that the TBTF problem is alleviated as the logarithmic slope of the central cusp becomes shallower. We find that the TBTF problem is avoided if the central cusps of DM haloes surrounding dSphs are shallower than $r^{-0.6}$.

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