Next-Generation Supernova Cosmology

Ia型超新星（SNe Ia）是一种优秀的宇宙探测器，对Ia型超新星的观测尤其擅长于限制当前宇宙膨胀率和暗能量的性质。这个项目将解决以下问题：宇宙的膨胀历史是什么？是什么推动了加速膨胀？“暗能量”是一个宇宙常数，一个更奇特的东西，还是我们需要重新评估我们的引力模型？哈勃常数的本地测量和远程测量之间的“紧张”是由系统误差引起的，还是它指向了新的物理学？作为这项研究的一部分，将向几名研究生和12名社区大学学生提供观察技术方面的培训。我们将通过公开讲座和媒体进行宣传，首席研究员将与代表性不足的学生合作，使他们从两年制大学过渡到四年制大学。该团队将进行两次低红移超新星Ia巡天，以(1)减少SN宇宙学中最大的系统不确定性来源，即低红移SN样本的光度校准，(2)进一步减少与尘埃变红和SN物理相关的其他系统学，(3)交叉校准世界上最好的两个光度系统，在这两个系统上将观察到1250个具有宇宙学意义的低红移超新星Ia。(4)用单一望远镜系统观测到第一个范围从0到0.8的Ia型超新星样本；(5)获得数百个Ia型超新星的光谱；(6)利用光谱数据检验潜在的距离改进；(7)对暗能量的性质和宇宙当前的膨胀率产生最严格的约束。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Type Ia supernovae (SNe Ia) are an excellent cosmological probe, and observations of SNe Ia are particularly good at constraining the current cosmic expansion rate and the nature of dark energy. This project will address the following questions: What is the expansion history of the Universe and what is driving the accelerated expansion? Is "dark energy" a cosmological constant, something more exotic, or do we need to re-evaluate our model of gravity? Is the "tension" between local and distant measurements of the Hubble constant caused by systematic errors, or does it point to new physics? As part of this research, training will be provided to several graduate students and 12 community-college students in observational techniques. Outreach will be undertaken through public lectures and the press, and the principle investigator will work with underrepresented students to transition from two-year colleges to four-year programs. The team will perform two low-redshift SNe Ia surveys to (1) reduce the largest source of systematic uncertainty in SN cosmology, the photometric calibration of the low-redshift SN sample, (2) further reduce other systematics related to dust reddening and SN physics, (3) cross-calibrate two of the world's best photometric systems on which 1250 cosmologically useful low-redshift SNe Ia will be observed, (4) produce the first sample of SNe Ia ranging from 0 z 0.8 observed with a single telescopic system, (5) obtain spectra of hundreds of SNe Ia, (6) examine potential distance improvements using spectral data, and (7) produce the tightest constraints on the nature of dark energy and current expansion rate of the Universe.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.