论文标题

一种新方法,用于重建具有分辨运动学的强镜星系

A New Method for the Reconstruction of Strongly Lensed Galaxies with Resolved Kinematics

论文作者

Young, Anthony J., Keeton, Charles R., Baker, Andrew J.

论文摘要

高红移星系的整体田间光谱已成为理解其动态和进化状态的强大工具。但是,在重力镜头系统的情况下,事实证明,很难以一种充分利用光谱域中可用信息的方式对镜头和内在的运动学进行建模。在本文中,我们介绍了一种基于像素的源重建的新方法,该方法以一种以物理动机但灵活的方式来利用运动学信息的方式来改变标准的正则化方案,以使二维数据的方式更适合整体现场数据的三维性质。为了评估这种方法的性能,我们将其结果与更传统的二维非参数方法的结果进行了比较。我们发现,3D正则化应用于整个数据立方体,比应用于单独的速度通道的2D正则化更准确地重建了源的强度和速度结构。用3D正则化重建的立方体也具有更均匀的噪声和分辨率,并且对单个速度通道的信噪比敏感不如2D正则化结果。我们可以实现对镜头系统进行整体现场观测的新方法,而无需对固有运动学的限制性进行限制性假设,并为新的观察策略打开了新的观测策略,这些策略优先于空间分辨率优先(例如,对于像Alma这样的多种配置阵列)。

Integral field spectroscopy of high-redshift galaxies has become a powerful tool for understanding their dynamics and evolutionary states. However, in the case of gravitationally lensed systems, it has proved difficult to model both lensing and intrinsic kinematics in a way that takes full advantage of the information available in the spectral domain. In this paper, we introduce a new method for pixel-based source reconstruction that alters standard regularization schemes for two-dimensional data in a way that leverages kinematic information in a physically motivated but flexible fashion, and that is better suited to the three-dimensional nature of integral field data. To evaluate the performance of this method, we compare its results to those of a more traditional two-dimensional non-parametric approach using mock ALMA observations of a typical high-redshift dusty star-forming galaxy. We find that 3D regularization applied to an entire data cube reconstructs a source's intensity and velocity structure more accurately than 2D regularization applied to separate velocity channels. Cubes reconstructed with 3D regularization also have more uniform noise and resolution properties and are less sensitive to the signal-to-noise ratio of individual velocity channels than the results of 2D regularization. Our new approach to modeling integral field observations of lensed systems can be implemented without making restrictive a priori assumptions about intrinsic kinematics, and opens the door to new observing strategies that prioritize spectral resolution over spatial resolution (e.g., for multi-configuration arrays like ALMA).

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