Developing galaxy-cluster potentials into a cosmological diagnostic

将星系团势发展为宇宙学诊断

• 批准号: 346672789
• 负责人: Professor Dr. Matthias Bartelmann
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/346672789?language=en
• 关键词: Developing; galaxy; cluster; potentials; into

Successful as the cosmological standard model is, its claim for dark matter and dark energy nonetheless poses hitherto unsolved fundamental questions. One of these questions concerns the possible time evolution of the dark energy, for which so far no clue could be found: The simplest, but at the same time least satisfactory explanation of dark energy from the point of view of particle physics is Einstein's cosmological constant. For our understanding of dark energy, it is fundamentally important to know whether the density of the dark energy is changing on cosmological time scales or not.Perhaps the only population of cosmic objects whose evolution depends sensitively enough on a possible time dependence of dark energy is the population of galaxy clusters. If it were possible to count galaxy clusters reliably enough depending on their distance and on at least one intrinsic parameter, a time evolution of the dark energy could be tracked down with substantially higher accuracy than so far possible.Conventionally, the mass of galaxy clusters is used as an internal parameter to establish the relation between observations and theoretical expectations. However, since the mass is neither directly observable nor can theoretically be predicted sufficiently precisely, this relation must be established by means of empirically calibrated scaling relations. Despite all successes, these relations still scatter so much that they are likely to veil the effects of a time dependence of the dark energy on the galaxy-cluster population.We propose to use the gravitational potential of the galaxy clusters instead of the mass to link observations with theory. As a local, directly measureable quantity, the potential has decisive advantages compared to the mass. Our previous work has shown how all available observables of galaxy clusters can be used to determine the potential and how the statistics of the galaxy-cluster population can be characterized theoretically based solely on the gravitational potential.In the project proposed here, we plan to join and integrate the methods we have so far developed, and to test beginning with realistically simulated data whether the resulting method will in fact reduce the scatter in the cosmological inference in the way expected. First applications to existing data will allow us to prepare for upcoming large surveys.

尽管宇宙学标准模型很成功，但它对暗物质和暗能量的主张仍然提出了迄今为止尚未解决的基本问题。其中一个问题涉及暗能量可能的时间演化，迄今为止还没有找到任何线索：从粒子物理学的角度来看，对暗能量最简单但同时最不令人满意的解释是爱因斯坦的宇宙学常数。对于我们对暗能量的理解，了解暗能量的密度是否在宇宙时间尺度上发生变化至关重要。也许，唯一其演化足够敏感地依赖于暗能量可能的时间依赖性的宇宙物体群体是星系团群体。如果能够根据星系团的距离和至少一个内在参数足够可靠地对星系团进行计数，那么就可以以比迄今为止更高的精度追踪暗能量的时间演化。传统上，星系团的质量被用作内部参数来建立观测结果与理论预期之间的关系。然而，由于质量既不能直接观察到，也不能在理论上足够精确地预测，因此必须通过经验校准的比例关系来建立这种关系。尽管取得了所有成功，这些关系仍然分散得如此之大，以至于它们很可能掩盖了暗能量对星系团群体的时间依赖性的影响。我们建议使用星系团的引力势而不是质量来将观测与理论联系起来。作为一个局部的、可直接测量的量，势与质量相比具有决定性的优势。我们之前的工作已经展示了如何使用星系团的所有可用观测值来确定引力势，以及如何仅根据引力势从理论上描述星系团总体的统计数据。在此提出的项目中，我们计划加入并整合我们迄今为止开发的方法，并从实际模拟数据开始测试所得方法是否实际上会以预期的方式减少宇宙学推断中的散射。对现有数据的首次应用将使我们能够为即将进行的大型调查做好准备。