Test of the equivalence principle for galaxy’s darkmatter by lunar laser ranging
Test of the equivalence principle for galaxy’s darkmatter by lunar laser ranging
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通过月球激光测距测试星系暗物质的等效原理
DOI：
10.1007/s10569-020-09964-6
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发表时间：
2020
影响因子：
1.6
通讯作者：
Liliane Biskupek
中科院分区：
文献类型：
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作者：
Mingyue Zhang;Jürgen Müller;Liliane Biskupek
经过50年的独特观测，月球激光测距（LLR）被用来测试爱因斯坦相对论的核心要素，比如引力常数或度量参数的可能的时间变化。在这里，我们关注的是由于假设银河系中心存在暗物质而可能违反等效原理（EP）的情况。根据EP的说法，地球和月球在包括银河系暗物质在内的任何物质的引力场中都会经历相同的加速度。在后一种情况下，对EP的破坏将导致以恒星月为周期的地月范围振荡。最近高精度的LLR测量为我们提供了对暗物质进行高精度EP测试的机会。我们从LLR拟合后的残差估计了可能的恒星范围振荡的振幅。首先，我们分析了每个站点的残差特征，并选择了一个最佳的LLR数据子集。利用这个数据集，我们获得了银河系中心方向的恒星振幅的最终结果为edmm（实际误差）。它强烈地限制了星系暗物质可能违反EP的可能性。我们的调查还表明，对于EP测试，良好的轨道覆盖和良好的数据比数据数量或长时间跨度更重要。作为验证，对非均匀LLR残差进行了光谱分析。再次，没有发现明显的恒星信号，证实了我们之前的结果。
Having 50 years of unique observations, lunar laser ranging (LLR) is used to test central elements of Einstein’s theory of relativity, like a possible temporal variation of the gravitational constant or metric parameters. Here, we focused on a possible violation of the equivalence principle (EP) due to assumed dark matter in the galactic center. According to the EP, Earth and Moon experience the same acceleration in the gravitational field of any matter including the galactic dark matter. In the latter case, a violation of the EP would cause an Earth–Moon range oscillation with a sidereal-month period. Recent LLR measurements with high accuracy give us the opportunity to carry out high-precision EP tests for dark matter. We estimated the amplitude of a possible sidereal range oscillation from LLR post-fit residuals. First, we analyzed the characteristics of the residuals for each station and selected a subset of best LLR data. Using this dataset, we obtainedmm (realistic error) as a final result for the sidereal amplitude in the direction of the galactic center. It strongly limits a possible violation of the EP for galaxy’s dark matter. Our investigations also show that, for the EP test, a good orbit coverage with good data is more relevant than the number of data or a long time span. As verification, a spectral analysis of the non-uniform LLR residuals has been performed. There again, no significant sidereal signal was found, confirming our previous result.