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arXiv 0804.0285astro-ph
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根据CMB数据估算暗物质-暗能量耦合偏置参数

Dark Matter - Dark Energy coupling biasing parameter estimates from CMB data

Giuseppe La Vacca, Loris P. L. Colombo, Luca Vergani, Silvio A. Bonometto

摘要:

当CMB数据被用来推导宇宙学参数时,它们的选择确实很重要:如果参数空间没有覆盖“真实”模型,一些参数值可能会有偏差。这是一个问题,因为很难将暗能量(DE)物理学参数化。我们通过数值实验来测试这种风险。我们创建人工数据的动态或耦合DE模型,然后使用MCMC技术来恢复模型参数,通过假设一个恒定的DE状态参数w和没有DM-DE耦合。对于考虑的DE电位,当不存在耦合时,不会出现严重偏倚。相反,当“真正的”宇宙学包括甚至只是轻微的DM-DE耦合时,ω_{o,c}以及由此而来的H_o和Ω_{o,m}会遭受严重的偏差。因此,在暗分量保持未知性质之前,允许考虑DM-DE耦合的自由度可能是重要的,甚至比增加考虑w(a)行为的参数的数量更重要。

英文摘要:

When CMB data are used to derive cosmological parameters, their very choice does matter: some parameter values can be biased if the parameter space does not cover the "true" model. This is a problem, because of the difficulty to parametrize Dark Energy (DE) physics. We test this risk through numerical experiments. We create artificial data for dynamical or coupled DE models and then use MCMC techniques to recover model parameters, by assuming a constant DE state parameter w and no DM--DE coupling. For the DE potential considered, no serious bias arises when coupling is absent. On the contrary, ω_{o,c}, and thence H_o and Ω_{o,m}, suffer a serious bias when the "true" cosmology includes even just a mild DM--DE coupling. Until the dark components keep an unknown nature, therefore, it can be important to allow for a degree of freedom accounting for DM--DE coupling, even more than increasing the number of parameters accounting for the w(a) behavior.

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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