Test of the FLRW Metric and Curvature with Strong Lens Time Delays
Test of the FLRW Metric and Curvature with Strong Lens Time Delays
复制标题
具有强透镜时间延迟的 FLRW 公制和曲率测试
DOI：
10.3847/1538-4357/aa697e
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发表时间：
2017-04-20
影响因子：
4.9
通讯作者：
Fan, Xi-Long
中科院分区：
文献类型：
--
作者：
Liao, Kai;Li, Zhengxiang;Fan, Xi-Long
We present a new model-independent strategy for testing the Friedmann-Lemaitre-Robertson-Walker (FLRW) metric and constraining cosmic curvature, based on future time-delay measurements of strongly lensed quasar-elliptical galaxy systems from the Large Synoptic Survey Telescope and supernova observations from the Dark Energy Survey. The test only relies on geometric optics. It is independent of the energy contents of the universe and the validity of the Einstein equation on cosmological scales. The study comprises two levels: testing the FLRW metric through the distance sum rule (DSR) and determining/ constraining cosmic curvature. We propose an effective and efficient (redshift) evolution model for performing the former test, which allows us to concretely specify the violation criterion for the FLRW DSR. If the FLRW metric is consistent with the observations, then on the second level the cosmic curvature parameter will be constrained to similar to 0.057 or similar to 0.041 (1 sigma), depending on the availability of high-redshift supernovae, which is much more stringent than current model-independent techniques. We also show that the bias in the time-delay method might be well controlled, leading to robust results. The proposed method is a new independent tool for both testing the fundamental assumptions of homogeneity and isotropy in cosmology and for determining cosmic curvature. It is complementary to cosmic microwave background plus baryon acoustic oscillation analyses, which normally assume a cosmological model with dark energy domination in the late-time universe.
