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A CMB foreground study in WMAP data: Extragalactic point sources and zodiacal light emission.

机译：WMAP数据中的CMB前景研究：河外点源和黄道发光。

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摘要

The Cosmic Microwave Background (CMB) radiation is the remnant heat from the Big Bang. It serves as a primary tool to understand the global properties, content and evolution of the universe. Since 2001, NASA's Wilkinson Microwave Anisotropy Probe (WMAP) satellite has been napping the full sky anisotropy with unprecedented accuracy, precision and reliability. The CMB angular power spectrum calculated from the WMAP full sky maps not only enables accurate testing of cosmological models, but also places significant constraints on model parameters. The CMB signal in the WMAP sky maps is contaminated by microwave emission from the Milky Way and from extragalactic sources. Therefore, in order to use the maps reliably for cosmological studies, the foreground signals must be well understood and removed from the maps. This thesis focuses on the separation of two foreground contaminants from the WMAP maps: extragalactic point sources and zodiacal light emission.;Extragalactic point sources constitute the most important foreground on small angular scales. Various methods have been applied to the WMAP single frequency maps to extract sources. However, due to the limited angular resolution of WMAP, it is possible to confuse positive CMB excursions with point sources or miss sources that are embedded in negative CMB fluctuations. We present a novel CMB-free source finding technique that utilizes the spectrum difference of point sources and CMB to form internal linear combinations of multifrequency maps to suppress the CMB and better reveal sources. When applied to the WMAP 41, 64 and 94 GHz maps, this technique has not only enabled detection of sources that are previously cataloged by independent methods, but also allowed disclosure of new sources. Without the noise contribution from the CMB, this method responds rapidly with the integration time. The number of detections varies as ∝ t0.72 in the two-band search and ∝ t 0.70 in the three-band search from one year to five years, separately, in comparison to t0.40 from the WMAP catalogs. Our source catalogs are a good supplement to the existing WMAP source catalogs, and the method itself is proven to be both complementary to and competitive with all the current source finding techniques in WMAP maps.;Scattered light and thermal emission from the interplanetary dust (IPD) within our Solar System are major contributors to the diffuse sky brightness at most infrared wavelengths. For wavelengths longer than 3.5 mum, the thermal emission of the IPD dominates over scattering, and the emission is often referred to as the Zodiacal Light Emission (ZLE). To set a limit of ZLE contribution to the WMAP data, we have performed a simultaneous fit of the yearly WMAP time-ordered data to the time variation of ZLE predicted by the DIRBE IPD model (Kelsall et al. 1998) evaluated at 240 mum, plus ℓ = 1 - 4 CMB components. It is found that although this fitting procedure can successfully recover the CMB dipole to a 0.5% accuracy, it is not sensitive enough to determine the ZLE signal nor the other multipole moments very accurately.
机译：宇宙微波背景（CMB）辐射是来自大爆炸的残余热量。它是了解宇宙的全局特性，内容和演化的主要工具。自2001年以来，NASA的威尔金森微波各向异性探测器（WMAP）卫星就以前所未有的精度，精确度和可靠性打入了整个天空的各向异性。根据WMAP的全天地图计算出的CMB角功率谱不仅可以精确测试宇宙学模型，而且对模型参数也有很大的限制。 WMAP天空图中的CMB信号被银河系和银河系外的微波辐射所污染。因此，为了可靠地将地图用于宇宙学研究，必须很好地理解前景信号并将其从地图中删除。本文着重从WMAP图中分离出两种前景污染物：河外点源和黄道发光。；河外点源在小角度尺度上是最重要的前景。已将各种方法应用于WMAP单频图以提取源。但是，由于WMAP的角度分辨率有限，可能会将正CMB偏移与嵌入在负CMB波动中的点源或遗漏源混淆。我们提出了一种新颖的无CMB的源发现技术，该技术利用点源和CMB的频谱差异来形成多频图的内部线性组合，从而抑制CMB并更好地揭示源。当应用于WMAP 41、64和94 GHz地图时，此技术不仅能够检测以前通过独立方法分类的源，而且还允许公开新的源。在没有CMB的噪声影响的情况下，该方法可以快速响应积分时间。与WMAP目录中的t0.40相比，分别从一年到五年，两波段搜索的检测次数变化为t0.72，三波段搜索的变化值为t 0.70。我们的源目录是对现有WMAP源目录的良好补充，并且该方法本身已被证明可与WMAP地图中的所有当前源查找技术互补并具有竞争力。;星际尘埃（IPD）产生的散射光和热辐射）是我们太阳系中对大多数红外波长的漫射天空亮度的主要贡献者。对于波长大于3.5微米的波长，IPD的热辐射在散射方面占主导地位，并且该辐射通常称为黄道发光（ZLE）。为了设置ZLE对WMAP数据的贡献的限制，我们对DMAP的IPD模型（Kelsall et al。1998）预测的ZLE的时间变化同时进行了WMAP年度排序数据的拟合（Kelsall等，1998），评估值为240 mum，加＆ell; = 1-4个CMB组件。已经发现，尽管该拟合过程可以成功地将CMB偶极子恢复到0.5％的精度，但是它不够灵敏，无法非常精确地确定ZLE信号或其他多极矩。

著录项

  • 作者

    Chen, Xi.;

  • 作者单位

    University of California, Los Angeles.;

  • 授予单位 University of California, Los Angeles.;
  • 学科 Physics Astrophysics.;Physics Astronomy and Astrophysics.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 166 p.
  • 总页数 166
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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