Elimination of H0 Systematics with Novel Analysis Techniques

这项研究旨在测量宇宙膨胀的速率（哈勃常数），其精度比以前更高。直到最近，用不同的技术测量哈勃常数--比较天体的视亮度和大小随着它们远离地球而变化--得到了一致的结果。然而，随着测量变得更加精确，这些不同的技术现在已经出现分歧。如果这种分歧是真实的，它将对我们理解宇宙学和基本物理概念产生深远的影响，比如“存在多少基本粒子？”目前，这些测量中的“张力”大到足以具有统计学显著性，但是考虑到戏剧性的含义，在确认张力是真实的之前需要进一步的独立验证。该计划的研究将使用“标准蜡烛”的观测提供哈勃常数的独立测量-其固有亮度可用于推断其距离的物体-其精度使其直接与竞争的“标准尺”技术的测量相媲美。我们将使用变星来解决这个问题，变星的内在亮度与它们的脉动周期直接相关。到目前为止，标准的做法一直是一次分析一个波长的可变星星数据，在事实发生后（如果有的话）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，使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，我们将减少标准烛光哈勃常数测量的不确定性。只有这样，我们才能确定最近哈勃常数测量的差异是否是由于实验误差，或者我们是否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.