论文标题
来自星系尺度强力镜头的Newtonian后参数和宇宙曲率的直接估计
Direct Estimate of the Post-Newtonian Parameter and Cosmic Curvature from Galaxy-scale Strong Gravitational Lensing
论文作者
论文摘要
爱因斯坦的一般相对论理论（GR）已在太阳系量表上进行了精确测试，但是乳乳外测试的进行较差。在这项工作中，我们使用了新汇编的星系尺度强力透镜样品，以测试GR在千帕斯克尺度上的有效性。 In order to solve the circularity problem caused by the preassumption of a specific cosmological model based on GR, we employ the distance sum rule in the Friedmann-Lema\^ıtre-Robertson-Walker metric to directly estimate the parameterized post-Newtonian (PPN) parameter $γ_{\rm PPN}$ and the cosmic curvature $Ω_k$ by combining observations of strong镜头和IA型超新星。这是$γ_ {\ rm ppn} $和$ω_k$的第一个同时测量，没有关于宇宙内容或重力理论的任何假设。我们的结果表明，$γ_ {\ rm ppn} = 1.11^{+0.11} _ { - 0.09} $和$ω__{k} = 0.48^{+1.09} _ { - 0.71} $，表明两个数量之间有强度的脱发。测量的$γ_ {\ rm ppn} $，与GR的预测相一致，它提供了GR的精确外乳术测试，其分数精度优于9.0 \％。如果采用了空间平坦的先验（即，$ω_{k} = 0 $），则可以将PPN参数约束进一步提高到$γ_ {\ rm ppn} = 1.07^{+0.07} _ {+0.07} _ { - 0.07} $，代表6.5 \％的精确度。另一方面，在GR（即$γ_ {\ rm ppn} = 1 $）的框架内，我们的结果仍然与零曲率（$ω__k= -0.12^{+0.48} _ { - 0.36} $）略微兼容，支持与平坦的flat flat flat flat flat flat flat flat flat flat flat flat flat flat flat flat flat flat flat flat flat flat flat。
Einstein's theory of general relativity (GR) has been precisely tested on solar system scales, but extragalactic tests are still poorly performed. In this work, we use a newly compiled sample of galaxy-scale strong gravitational lenses to test the validity of GR on kiloparsec scales. In order to solve the circularity problem caused by the preassumption of a specific cosmological model based on GR, we employ the distance sum rule in the Friedmann-Lema\^ıtre-Robertson-Walker metric to directly estimate the parameterized post-Newtonian (PPN) parameter $γ_{\rm PPN}$ and the cosmic curvature $Ω_k$ by combining observations of strong lensing and Type Ia supernovae. This is the first simultaneous measurement of $γ_{\rm PPN}$ and $Ω_k$ without any assumptions about the contents of the universe or the theory of gravity. Our results show that $γ_{\rm PPN}=1.11^{+0.11}_{-0.09}$ and $Ω_{k}=0.48^{+1.09}_{-0.71}$, indicating a strong degeneracy between the two quantities. The measured $γ_{\rm PPN}$, which is consistent with the prediction of 1 from GR, provides a precise extragalactic test of GR with a fractional accuracy better than 9.0\%. If a prior of the spatial flatness (i.e., $Ω_{k}=0$) is adopted, the PPN parameter constraint can be further improved to $γ_{\rm PPN}=1.07^{+0.07}_{-0.07}$, representing a precision of 6.5\%. On the other hand, in the framework of GR (i.e., $γ_{\rm PPN}=1$), our results are still marginally compatible with zero curvature ($Ω_k=-0.12^{+0.48}_{-0.36}$), supporting no significant deviation from a flat universe.
