arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1904.08400astro-ph.GA
收藏

来自强透镜的星系质量分布I：圆幂律模型

Galaxy mass profiles from strong lensing I: The circular power-law model

Conor M. O'Riordan, Stephen J. Warren, Daniel J. Mortlock

备注：
12 pages, 5 figures. Accepted for publication in MNRAS
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

在这一系列的论文中，我们开发了一个形式主义的约束质量分布在强引力透镜与扩展的图像，使用通量除了位置信息。我们开始在本文中与圆形幂律的轮廓，并表明，斜率$γ$是唯一确定的只有两个观测值：流量比$f_1/f_2$和图像的位置比$θ_1/θ_2$的两个图像。我们推导出一个解析表达式，这两个可观的斜率，结果不依赖于爱因斯坦角或结构或亮度的来源。然后，我们找到一个表达式的斜率$σ_γ$的不确定性，只依赖于位置比$θ_1/θ_2$和总的S/N的图像。例如，在具有位置比$θ_1/θ_2=0.5$、S/N $=100$和$γ=2$的系统中，我们发现$γ$被约束到$\pm0.03$的精度。然后，我们测试这些结果对一系列的模拟观察。我们反演图像并拟合一个11参数模型，包括透镜和光源的椭圆度和位置角，并测量$γ$上的不确定度。我们发现协议的理论估计所有模拟观测。在未来的论文中，我们将研究的径向范围内的星系的约束的斜率适用，并扩展到椭圆透镜的分析。

英文摘要：

In this series of papers we develop a formalism for constraining mass profiles in strong gravitational lenses with extended images, using fluxes in addition to positional information. We start in this paper with a circular power-law profile and show that the slope $γ$ is uniquely determined by only two observables: the flux ratio $f_1/f_2$ and the image position ratio $θ_1/θ_2$ of the two images. We derive an analytic expression relating these two observables to the slope, a result which does not depend on the Einstein angle or the structure or brightness of the source. We then find an expression for the uncertainty on the slope $σ_γ$ that depends only on the position ratio $θ_1/θ_2$ and the total S/N in the images. For example, in a system with position ratio $θ_1/θ_2=0.5$, S/N $=100$ and $γ=2$ we find that $γ$ is constrained to a precision of $\pm0.03$. We then test these results against a series of mock observations. We invert the images and fit an 11 parameter model, including ellipticity and position angle for both lens and source and measure the uncertainty on $γ$. We find agreement with the theoretical estimate for all mock observations. In future papers we will examine the radial range of the galaxy over which the constraint on the slope applies, and extend the analysis to elliptical lenses.

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。

↑