分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: We discover a linear relation between two sets of galaxy-lensing cross-correlations. This linear relation holds, as long as light follows the geodesic and the metric is Friedmann-Lema\^{i}tre-Robertson-Walker (FLRW). Violation of the cosmological principle (and equivalently the FLRW metric) will break this linear relation. Therefore it provides a powerful test of the cosmological principle, based on direct observables and relied on no specific cosmological models. We demonstrate that stage IV galaxy surveys and CMB-S4 experiments will be able to test this linear relation stringently and therefore test the cosmological principle robustly.
分类: 天文学 >> 天文学 提交时间: 2023-02-19
摘要: The cosmological luminosity-distance can be measured from gravitational wave (GW) standard sirens, free of astronomical distance ladders and the associated systematics. However, it may still contain systematics arising from various astrophysical, cosmological and experimental sources. With the large amount of dark standard sirens of upcoming third generation GW experiments, such potential systematic bias can be diagnosed and corrected by statistical tools of the large scale structure of the universe. We estimate that, by cross-correlating the dark siren luminosity-distance space distribution and galaxy redshift space distribution, multiplicative error $m$ in the luminosity distance measurement can be constrained with $1\sigma$ uncertainty $\sigma_m\sim 0.1$. This is already able to distinguish some binary black hole origin scenarios unambiguously. Significantly better constraints and therefore more applications may be achieved by more advanced GW experiments.