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。 这一混合方案有一个机会跟踪目标部分和一个调查部分。 该调查将战略性地覆盖许多黑洞事件的感兴趣区域。 它将收集一个引力波触发的中子星星合并事件的样本和一个黑洞合并的样本，这些样本的潜在宿主星系已经被编目。 宇宙膨胀率是现代宇宙学中的一个关键参数。 目前，局部测量和宇宙微波背景研究的结果之间存在紧张关系，这促使人们追求改进的独立观测值：引力波长期以来一直被认为是这样的。 这项工作包括两个这样的选择。 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的沟通，包括目前在STEM领域代表性不足的大学前青少年。 研究人员将利用布兰迪斯科学传播实验室的基础设施，与高中进行接触，并强调代表性不足的群体。这项研究使用了NSF位于智利的布兰科4米望远镜上的暗能量相机（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。 它还将使用来自另一个NSF设施的数据，激光干涉仪引力波天文台，LIGO。 所用的方法包括一个适合于中子星星合并样本的哈勃图和一个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，因为标准海妖是完全基于广义相对论的距离指示器。 2015年，具有足够灵敏度的探测器开始投入使用。 这项研究将充分利用新的数据集作为宇宙学的多信使探针，使用DES/DECam数据，测量3-5%的膨胀率到2022年的不确定性，并启用百分比-该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准。

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.