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arXiv 2102.08973astro-ph.GA
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统计强透镜效应。I.来自一千个透镜样品对星系内部结构的约束

Statistical strong lensing. I. Constraints on the inner structure of galaxies from samples of a thousand lenses

Alessandro Sonnenfeld, Marius Cautun

摘要:

背景:已知的强引力透镜的数量预计将在未来几年内大幅增长。大样本透镜的统计组合有可能对星系的内部结构提供强有力的约束。目的:我们调查到什么程度,我们可以校准恒星质量测量和约束的平均暗物质密度分布的星系统计结合强透镜数据从数千个镜头。方法:我们生成轴对称透镜的模拟样本。我们假设,对于每个镜头,我们有一个强透镜背景源的两个图像位置的测量,以及放大信息从全表面亮度建模,和一个恒星星族合成为基础的估计透镜恒星质量。然后,我们拟合模型描述的恒星人口合成失配参数$α_{sps}$(真实的恒星质量和恒星星族合成为基础的估计之间的比率)和暗物质密度分布的人口透镜的合奏1000模拟透镜。结果如下:与现有的约束条件相比,该方法可以得到平均$α_{sps}$、投影暗物质质量和暗物质密度斜率,具有很高的精度和准确度。为了避免有偏见的推断,需要灵活的模型和作为图像配置的函数的透镜检测效率的知识。结论:从即将到来的调查统计强透镜推论有可能校准恒星质量测量和约束大质量星系的内部暗物质密度分布。

英文摘要:

Context: The number of known strong gravitational lenses is expected to grow substantially in the next few years. The statistical combination of large samples of lenses has the potential of providing strong constraints on the inner structure of galaxies. Aims: We investigate to what extent we can calibrate stellar mass measurements and constrain the average dark matter density profile of galaxies by statistically combining strong lensing data from thousands of lenses. Methods: We generate mock samples of axisymmetric lenses. We assume that, for each lens, we have measurements of two image positions of a strongly lensed background source, as well as magnification information from full surface brightness modelling, and a stellar population synthesis-based estimate of the lens stellar mass. We then fit models describing the distribution of the stellar population synthesis mismatch parameter $α_{sps}$ (the ratio between the true stellar mass and the stellar population synthesis-based estimate) and dark matter density profile of the population of lenses to an ensemble of 1000 mock lenses. Results: The average $α_{sps}$, projected dark matter mass and dark matter density slope can be obtained with great precision and accuracy, compared with current constraints. A flexible model and the knowledge of the lens detection efficiency as a function of image configuration are required in order to avoid a biased inference. Conclusions: Statistical strong lensing inferences from upcoming surveys have the potential to calibrate stellar mass measurements and to constrain the inner dark matter density profile of massive galaxies.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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