Observing LIGO/Virgo-triggered neutron star mergers with the Dark Energy Camera: a new path for Cosmology

该项目将对宇宙膨胀率进行精确测量。这一混合计划有一个机会跟踪目标部分和一个调查部分。这项调查将战略性地涵盖许多黑洞事件的感兴趣区域。它将收集引力波引发的中子星合并事件的样本，以及已经为潜在宿主星系编目的黑洞合并样本。宇宙膨胀率是现代宇宙学中的一个关键参数。目前，当地的测量结果与宇宙微波背景研究的结果之间存在紧张关系，这促使人们追求更好的独立观测数据：引力波长期以来一直被认为是这样的。这项工作涵盖了两种这样的选择。扩大研究对整个社会的影响需要与来自不同背景的受众进行有效沟通，包括目前在STEM领域代表性不足的大学前青少年。这位研究人员将利用布兰代斯科学传播实验室的基础设施，与高中接触并强调代表不足的群体。这项研究使用了美国国家科学基金会智利布兰科4米望远镜上暗能量相机(DECAM)的全部可用数据，包括作为暗能量调查(DES)的一部分拍摄的图像，以及非DES DECAM图像。它还将使用来自NSF的另一个设施--激光干涉仪引力波天文台(LIGO)的数据。使用的方法包括适合中子星合并样本的哈勃图表和黑洞事件的统计暗警报分析。这是一种独立于其他宇宙学探测器的新方法，因为标准警报器是完全基于广义相对论的距离指示器。具有足够灵敏度以实现这一方法的探测器于2015年投入使用。这项研究将充分利用新的数据集作为宇宙学的多信使探测器，使用DES/DECAM数据，到2022年以3-5%(统计)不确定度测量膨胀率，并使用来自大型天气观测望远镜等设施的未来数据实现百分比级别的精度。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will make a precision measurement of the cosmic expansion rate. This hybrid program has a target of opportunity follow-up component and a survey component. The survey will strategically cover the regions of interest of many black hole events. It will collect a sample of gravitational-wave triggered neutron star merger events and a sample of black hole mergers for which potential host galaxies have been cataloged. The rate of cosmic expansion is a key parameter in modern cosmology. There is currently tension between local measurements and the results from cosmic microwave background studies, which motivates the pursuit of improved independent observables: gravitational waves have long been proposed as one such. This work covers two such alternatives. Broadening the impact of research on society at large requires effective communication to audiences from diverse backgrounds, including pre-college teens currently under-represented in STEM fields. The researcher will engage with high schools and emphasize under-represented groups, using the infrastructure of the Brandeis Science Communication Laboratory.This study uses the full range of available data from the Dark Energy Camera (DECam) on NSF's Blanco 4-meter telescope in Chile, including images taken as part of the Dark Energy Survey (DES), as well as non-DES DECam images. It will also use data from another NSF facility, the Laser Interferometer Gravitational-wave Observatory, LIGO. Methods to be used include a Hubble diagram fit to a sample of neutron star mergers and a statistical dark sirens analysis for black hole events. This is a new method independent of other cosmological probes, because standard sirens are distance indicators based solely on general relativity. Detectors with enough sensitivity to enable this approach became operational in 2015. This research will fully exploit the novel datasets as multi-messenger probes for cosmology using DES/DECam data, making a measurement of the expansion rate with 3-5% (statistical) uncertainty by 2022, and enabling percent-level precision with future data from facilities like the Large Synoptic Survey Telescope.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.