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arXiv 1505.05511astro-ph.COgr-qchep-ph
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衰变暗物质和$σ_8$中的张力

Decaying dark matter and the tension in $σ_8$

Kari Enqvist, Seshadri Nadathur, Toyokazu Sekiguchi, Tomo Takahashi

摘要:

我们认为衰变暗物质(DDM)作为宇宙微波背景(CMB)和弱透镜(WL)之间可能存在的紧张关系的解决方案的物质波动的振幅,$σ_8$的测定。我们在一个暗物质衰变为暗辐射的模型中进行了N体模拟,得到了非线性物质功率谱的精确拟合公式,从而使我们能够通过CMB、WL和重子声学振荡(BAO)的联合测量来检验DDM模型.我们采用马尔可夫链蒙特卡罗分析来研究宇宙学参数的后验分布的重叠,比较CMB单独与WL+BAO。我们发现一个重叠,是显着更大的DDM模型比标准的CDM模型。这可能暗示了DDM,尽管目前的数据还不足以明确地支持非零的暗物质衰变率$Γ$。从组合的CMB+WL数据中,我们获得了95%C.L下的下限$Γ^{-1}\ge 97$ Gyr,其比单独来自CMB的约束更不紧密。

英文摘要:

We consider decaying dark matter (DDM) as a resolution to the possible tension between cosmic microwave background (CMB) and weak lensing (WL) based determinations of the amplitude of matter fluctuations, $σ_8$. We perform N-body simulations in a model where dark matter decays into dark radiation and develop an accurate fitting formula for the non-linear matter power spectrum, which enables us to test the DDM model by the combined measurements of CMB, WL and the baryon acoustic oscillation (BAO). We employ a Markov chain Monte Carlo analysis to examine the overlap of posterior distributions of the cosmological parameters, comparing CMB alone with WL+BAO. We find an overlap that is significantly larger in the DDM model than in the standard CDM model. This may be hinting at DDM, although current data is not constraining enough to unambiguously favour a non-zero dark matter decay rate $Γ$. From the combined CMB+WL data, we obtain a lower bound $Γ^{-1}\ge 97$ Gyr at 95 % C.L, which is less tight than the constraint from CMB alone.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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