We review three distance measurement techniques beyond the local universe: (1) gravitational lens time delays, (2) baryon acoustic oscillation (BAO), and (3) HI intensity mapping. We describe the principles and theory behind each method, the ingredients needed for measuring such distances, the current observational results, and future prospects. Time-delays from strongly lensed quasars currently provide constraints on H0$H_{0}$ with <4%$<4\%$ uncertainty, and with 1%$1\%$ within reach from ongoing surveys and efforts. Recent exciting discoveries of strongly lensed supernovae hold great promise for time-delay cosmography. BAO features have been detected in redshift surveys up to z≲0.8$z\lesssim0.8$ with galaxies and z∼2$z\sim2$ with Ly-α$\alpha$ forest, providing precise distance measurements and H0$H_{0}$ with <2%$<2\%$ uncertainty in flat Λ$\Lambda$CDM. Future BAO surveys will probe the distance scale with percent-level precision. HI intensity mapping has great potential to map BAO distances at z∼0.8$z\sim0.8$ and beyond with precisions of a few percent. The next years ahead will be exciting as various cosmological probes reach 1%$1\%$ uncertainty in determining H0$H_{0}$, to assess the current tension in H0$H_{0}$ measurements that could indicate new physics.

中文翻译：

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宇宙距离指标

我们回顾了本地宇宙之外的三种距离测量技术：（1）引力透镜时间延迟，（2）重子声振荡（BAO）和（3）HI强度映射。我们描述了每种方法背后的原理和理论、测量这种距离所需的成分、当前的观测结果和未来的前景。来自强透镜类星体的时间延迟目前对 H0$H_{0}$ 提供了限制，不确定性<4%$<4\%$，正在进行的调查和努力可以达到 1%$1\%$。最近对强透镜超新星的激动人心的发现为时延宇宙学带来了巨大希望。BAO 特征已经在红移测量中被检测到 z≲0.8$z\lesssim0.8$ 与星系和 z∼2$z\sim2$ 与 Ly-α$\alpha$ 森林，提供精确的距离测量和 H0$H_{ 0}$ <2%$< 2\%$ 平坦 Λ$\Lambda$CDM 的不确定性。未来的 BAO 调查将以百分比精度探测距离尺度。HI 强度映射具有很大的潜力，可以以几个百分点的精度绘制 z∼0.8$z\sim0.8$ 及以上的 BAO 距离。未来几年将是令人兴奋的，因为各种宇宙学探测器在确定 H0$H_{0}$ 时达到 1%$1\%$ 的不确定性，以评估 H0$H_{0}$ 测量中的当前张力，这可能表明新物理学。