Elimination of H0 Systematics with Novel Analysis Techniques

这项研究的目的是测量宇宙膨胀的速度（哈勃常数），达到比以前更高的精度。直到最近，用不同的技术测量哈勃常数——比较天体在远离地球时的表观亮度和大小的变化——得出了一致的结果。然而，随着测量变得更加精确，这些不同的技术现在已经分道扬镳。如果这种分歧是真实的，它将对我们的理解产生深远的影响，不仅是对宇宙学的理解，而且对诸如“存在多少基本粒子？”等基本物理概念的理解。目前，这些测量中的“张力”足够大，具有统计学意义，但考虑到戏剧性的影响，在确认张力是真实的之前，需要进一步的独立验证。这个项目的研究将提供哈勃常数的独立测量，使用“标准蜡烛”的观测——物体的内在亮度可以用来推断它们的距离——其精度使其与竞争对手的“标准尺子”技术的测量结果直接相当。我们将用变星来解决这个问题；本质亮度与其脉动周期直接相关的恒星。到目前为止，标准的做法是每次分析一个波长的变星数据，在事实（如果有的话）之后与理论模型进行比较。这里提出的技术利用了我们今天拥有的大量数据，利用一组恒星的所有可用数据，结合恒星模型，以确保我们的测量尽可能准确和精确。通过在分析中包括所有可用的数据，我们将减少测量标准烛光哈勃常数的不确定性。只有这样，我们才能确定最近哈勃常数测量的差异是由于实验错误造成的，还是我们需要重新思考我们对宇宙的了解。

This study aims to measure the rate at which the Universe is expanding (the Hubble constant) to a higher precision than has been achieved before. Until recently, measurements of the Hubble constant from different techniques - comparing how the apparent brightness and size of astronomical objects change as they get further away from Earth - gave consistent results. However, as measurements have become more precise these different techniques have now diverged. If this divergence is real it will have profound implications for our understanding not just of cosmology, but of fundamental physics concepts such as 'how many fundamental particles exist?'.Currently the 'tension' in these measurements is large enough to be statistically significant, but given the dramatic implications, further independent verification is required before it is confirmed that the tension is real. The research in this program will provide an independent measurement of the Hubble constant using observations of 'standard candles' - objects whose intrinsic brightness can be used to infer their distance - with a precision that makes it directly comparable to measurements from the competing 'standard ruler' technique. We will tackle the problem using variable stars; stars whose intrinsic brightness are directly related to their pulsation period. Until now, standard practice has been to analyse variable star data one wavelength at a time, making comparisons with theoretical models after the fact (if at all). The technique proposed here takes advantage of the vast amount of data we have today, using all available data on a set of stars, combined with stellar models, to ensure that our measurements are as accurate and precise as possible. By including all available data in the analysis, we will reduce the uncertainty in our measurement of the standard candle Hubble constant. Only then can we determine whether or not the differences in recent Hubble constant measurements are due to experimental error, or if we need to rethink what we know about our Universe.