arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1602.02750astro-ph.CO
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宇宙物质密度场与原始磁场的演化

Evolution of the cosmic matter density field with a primordial magnetic field

Dai G. Yamazaki

摘要:

宇宙磁场影响宇宙物质密度场的时间演化。宇宙流体的阿尔芬速度的平方与原始磁场(PMF)的系综平均能量密度成正比,它阻止了物质密度场在视界尺度上的坍缩。物质辐射均等时间也被PMF的系综平均能量密度的存在延迟。PMF的系综平均能量密度也通过Meszaros效应和势衰变影响物质功率谱。由于PMF的系综平均能量密度在宇宙学线性微扰方程中不是一阶微扰,而是零阶源,为了正确理解PMF对MPS的整体影响,我们应该对以往研究PMF对MPS的方法进行重大修改,在线性微扰理论中同时考虑PMF的零阶和一阶源的影响。我们首次将保偏光纤中零阶源的影响应用到MPS的理论计算中。我们还分析了整体PMF对MPS的影响。弱透镜效应对CMB偏振态有影响。弱透镜效应由MPS决定。因此,我们必须考虑保偏光纤的零阶源,以便不仅正确理解MPS,而且正确理解CMB偏振。

英文摘要:

A cosmological magnetic field affects the time evolution of the cosmic matter density field. The squared Alfven velocity of the cosmic fluid is proportional to an ensemble average energy density of a primordial magnetic field (PMF), and it prevents the matter density field from collapsing in the horizon scale. The matter-radiation equality time also is delayed by the presence of an ensemble average energy density of a PMF. The ensemble average energy density of the PMF also affects the matter power spectrum (MPS) through the Meszaros effect and the potential decay. Since the ensemble average energy density of the PMF is not a first order perturbation but a zero order source in the linear perturbation equations for the cosmology, to correctly understand the overall effects of the PMF on the MPS, we should significantly revise previous approaches to research for the MPS with the PMF by considering both the effects of the zero and first order sources from the PMF in the linear perturbation theory. We apply the effects of the zero order sources from the PMF to theoretical computations of the MPS for the first time. We also analyze the overall PMF effects on the MPS. The CMB polarizations are affected the weak lensing. The weak lensing is determined by the MPS. Therefore, we have to consider the zero order sources of the PMF to gain a correct understanding not only of the MPS but also the CMB polarization.

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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