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Future Probes of Cosmology and the High-Redshift Universe.

机译：宇宙学和高红移宇宙的未来探索。

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摘要

This thesis is a study in theoretical cosmology with an emphasis on the high-redshift universe and promising directions for future observations. In Chapters 2 and 3, we propose intensity mapping of spectral line emission from galaxies. This is a technique to observe the cumulative emission from many galaxies without resolving individual sources. We use analytic calculations and N-body simulations to predict the observational signal for different emission lines, including those from oxygen, carbon monoxide, and carbon.;In Chapter 4, we utilize the Fisher matrix formalism to determine how accurately futuristic 21cm observatories, dedicated to post-reionization redshifts, can constrain cosmological parameters. We find that these experiments may yield significantly better constraints than next generation Cosmic Microwave Background (CMB) experiments such as the Planck telescope.;In Chapter 5, we perform semi-numerical simulations of reionization including a significant contribution from X-rays. We find that the large mean-free-path of X-rays adds a uniform component to reionization. Using these simulations, we compute the impact on the kinetic Sunyaev-Zel'dovich effect and find that a contribution from X-rays could result in a lower value of the so-called ``patchy reionization'' component of the CMB power spectrum.;In Chapter 6, we present the first realistic simulations of the 3-dimensional distribution of the first galaxies including the newly discovered relative velocity between baryons and dark matter. We use these simulations to compute the 21cm signal at redshift 20 and find that the relative velocity effect enhances fluctuations on a scale of 100 Mpc, making observations more feasible than previously expected.;In the final chapter, we propose that the physics which sets the density profiles of dark matter halos can be understood in terms of dissipationless gravitational collapse in non-cosmological simulations. To explore this, we run N-body collapse simulations from cold and spherically symmetric initial conditions. We find that the final equilibrium states of these simulations have some common features with dark matter halos, including the form of the pseudo-phase-space density.
机译：本文是对理论宇宙学的研究，重点是高红移宇宙和未来观测的有希望的方向。在第二章和第三章中，我们提出了星系光谱线发射的强度映射。这是一种无需解析单个源即可观察到许多星系累积发射的技术。我们使用分析计算和N体模拟来预测不同发射线（包括来自氧气，一氧化碳和碳的发射线）的观测信号;在第4章中，我们利用Fisher矩阵形式来确定未来派21cm天文台的精确程度再电离后的红移，可以约束宇宙学参数。我们发现这些实验可能比下一代宇宙微波背景（CMB）实验（例如普朗克望远镜）产生更好的约束。在第5章中，我们进行了电离的半数值模拟，其中包括X射线的显着贡献。我们发现，X射线的较大的平均自由程为电离增加了一个统一的分量。使用这些模拟，我们计算了对动力学Sunyaev-Zel'dovich效应的影响，发现X射线的贡献可能导致CMB功率谱中所谓的``斑片式电离''分量值降低。 ；在第6章中，我们给出了第一个星系3维分布的第一个现实模拟，包括新发现的重子与暗物质之间的相对速度。我们使用这些模拟来计算红移20处的21cm信号，发现相对速度效应在100 Mpc的尺度上增加了波动，使观测比以前预期的更可行。在最后一章中，我们建议将物理场设置为暗物质晕的密度分布可以通过非宇宙学模拟中的无耗散重力坍塌来理解。为了探索这一点，我们从冷的和球对称的初始条件运行N体崩溃模拟。我们发现这些模拟的最终平衡态具有暗物质晕的一些共同特征，包括伪相空间密度的形式。

著录项

  • 作者

    Visbal, Elijah Francis.;

  • 作者单位

    Harvard University.;

  • 授予单位 Harvard University.;
  • 学科 Physics Astrophysics.;Physics General.
  • 学位 Ph.D.
  • 年度 2013
  • 页码 229 p.
  • 总页数 229
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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