标题： 宇宙微波背景各向异性：开放问题 显示英文标题

标题： The Cosmic Microwave Background anisotropies: open problems

摘要： 标准暴胀模型提供了一个简单的场景，在这个场景中，宇宙的均匀性、各向同性和平坦性自然地成为其结果，并且能量密度的涨落起源于暴胀阶段。 这些原始的能量密度涨落导致了宇宙微波背景（CMB）在解耦表面的温度涨落。 之后，CMB光子几乎自由传播，与大尺度结构（LSS）中物质分布的演化引力场有轻微的引力相互作用，并且在宇宙再电离后与自由电子的散射率较低。 这些次级效应略微改变了辐射强度和极化角功率谱（APS）的形状。 APS包含了关于表征宇宙背景模型参数以及表征物质密度扰动和引力波功率谱参数的非常有价值的信息。 在过去的几年里，灵敏实验的数据使得我们可以很好地确定APS的形状，首次提供了接近空间平坦的宇宙模型。 特别是WMAP第一年的数据，连同其他更高分辨率的CMB数据和其他宇宙学数据集，使得我们能够以百分之几的精度确定宇宙学参数。 由此得出的宇宙模型最显著的特点是其大部分能量内容的未知性质。 这一问题以及其他宇宙学中的开放问题为CMB社区带来了令人兴奋的挑战。 未来的ESA普朗克任务无疑将为这些问题提供一些线索。 显示英文摘要

摘要： The standard inflationary model presents a simple scenario within which the homogeneity, isotropy and flatness of the universe appear as natural outcomes and, in addition, fluctuations in the energy density are originated during the inflationary phase. These seminal density fluctuations give rise to fluctuations in the temperature of the Cosmic Microwave Background (CMB) at the decoupling surface. Afterward, the CMB photons propagate almost freely, with slight gravitational interactions with the evolving gravitational field present in the large scale structure (LSS) of the matter distribution and a low scattering rate with free electrons after the universe becomes reionized. These secondary effects slightly change the shape of the intensity and polarization angular power spectra (APS) of the radiation. The APS contain very valuable information on the parameters characterizing the background model of the universe and those parametrising the power spectra of both matter density perturbations and gravitational waves. In the last few years data from sensitive experiments have allowed a good determination of the shape of the APS, providing for the first time a model of the universe very close to spatially flat. In particular the WMAP first year data, together with other CMB data at higher resolution and other cosmological data sets, have made possible to determine the cosmological parameters with a precision of a few percent. The most striking aspect of the derived model of the universe is the unknown nature of most of its energy contents. This and other open problems in cosmology represent exciting challenges for the CMB community. The future ESA Planck mission will undoubtely shed some light on these remaining questions.