Reionization Revisited: Secondary Cosmic Microwave Background Anisotropies and Polarization
Reionization Revisited: Secondary Cosmic Microwave Background Anisotropies and Polarization
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DOI：
10.1086/308279
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发表时间：
1999-07
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影响因子：
--
通讯作者：
Wayne Hu
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文献类型：
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作者：
Wayne Hu
次级宇宙微波背景（CMB）的各向异性和极化提供了研究再电离时代结构形成的实验室。我们从轻度非线性的大尺度结构考虑动力学的Sunyaev-Zeldovich效应，并表明它是微扰Vishniac效应的自然延伸。如果气体追踪暗物质到10阶的超密度，正如模拟所预期的那样，这种效应至少可以与弧分尺度下的维什尼亚克效应相媲美。在较小的尺度上，它可以用来研究气体的热历史相关的集群。极化是通过汤姆逊散射的原始四极各向异性，动力学（二阶多普勒）四极各向异性，和本质散射四极各向异性。小尺度极化是由这些源的密度和电离调制引起的。这些效应一般会产生类似的E-和B-宇称极化，但在绝热冷暗物质（CDM）模型中的振幅可以忽略不计（10 - 3 - 10 - 2 μ K）。然而，原始和动力学四极是目前观测可比的，所以零检测B-极化将设置速度场的演化和相干性的限制。相反，即使在大角度下探测到宇宙学的B偏振，也不一定意味着存在重力波或涡旋。对于这些计算，我们开发了一个全天空概括的Limber方程，允许任意的本地角度依赖的源标量和对称的无迹张量场的天空。
Secondary cosmic microwave background (CMB) anisotropies and polarization provide a laboratory for studying structure formation in the reionized epoch. We consider the kinetic Sunyaev-Zeldovich effect from mildly nonlinear large-scale structure and show that it is a natural extension of the perturbative Vishniac effect. If the gas traces the dark matter to overdensities of order 10, as expected from simulations, this effect is at least comparable to the Vishniac effect at arcminute scales. On smaller scales, it can be used to study the thermal history-dependent clustering of the gas. Polarization is generated through Thomson scattering of primordial quadrupole anisotropies, kinetic (second-order Doppler) quadrupole anisotropies, and intrinsic-scattering quadrupole anisotropies. Small-scale polarization results from the density and ionization modulation of these sources. These effects generically produce comparable E- and B-parity polarization, but of negligible amplitude (10-3-10-2 μK) in adiabatic cold dark matter (CDM) models. However, the primordial and kinetic quadrupoles are observationally comparable at present, so that a null detection of B-polarization would set constraints on the evolution and coherence of the velocity field. Conversely, the detection of a cosmological B-polarization even at large angles does not necessarily imply the presence of gravity waves or vorticity. For these calculations, we develop an all-sky generalization of the Limber equation that allows for an arbitrary local angular dependence of the source for both scalar and symmetric trace-free tensor fields on the sky.