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arXiv 1107.4629astro-ph.COastro-ph.IM
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利用太空观测对地基透镜数据进行精确模拟

Precision simulation of ground-based lensing data using observations from space

Rachel Mandelbaum, Christopher M. Hirata, Alexie Leauthaud, Richard J. Massey, Jason Rhodes

摘要:

目前和即将到来的宽视场、地基、宽带成像巡天有望解决星系形成和宇宙学中的一系列悬而未决的问题。对地面数据的几种这样的使用,特别是弱引力透镜,需要对星系图像统计进行高度精确的测量,并仔细校正点扩散函数(PSF)的影响。在本文中,我们介绍了SHERA(剪切卷积分析)软件来模拟地面成像数据与现实的星系形态和观测条件,从天基数据(来自COSMOS,宇宙演化调查)和占天基PSF的影响。该代码模拟地面数据,可选择地应用弱透镜剪切,以模型独立的方式使用一般傅立叶空间形式主义。这条管道的效用是,它允许精确,现实的评估系统误差由于数据处理方法,例如在提取弱透镜星系形状测量或星系径向轮廓,给定用户提供的观测条件和真实的星系形态。此外,模拟允许的误差估计和确定参数退化的经验测试,通过生成许多噪声地图。该软件的公开发布,以及大量清洁的COSMOS星系图像样本(纠正电荷转移效率低下),应该能够使即将到来的地基成像调查在精确弱透镜分析,星系轮廓测量和其他涉及详细图像分析的应用领域实现其潜力。

英文摘要:

Current and upcoming wide-field, ground-based, broad-band imaging surveys promise to address a wide range of outstanding problems in galaxy formation and cosmology. Several such uses of ground-based data, especially weak gravitational lensing, require highly precise measurements of galaxy image statistics with careful correction for the effects of the point-spread function (PSF). In this paper, we introduce the SHERA (SHEar Reconvolution Analysis) software to simulate ground-based imaging data with realistic galaxy morphologies and observing conditions, starting from space-based data (from COSMOS, the Cosmological Evolution Survey) and accounting for the effects of the space-based PSF. This code simulates ground-based data, optionally with a weak lensing shear applied, in a model-independent way using a general Fourier space formalism. The utility of this pipeline is that it allows for a precise, realistic assessment of systematic errors due to the method of data processing, for example in extracting weak lensing galaxy shape measurements or galaxy radial profiles, given user-supplied observational conditions and real galaxy morphologies. Moreover, the simulations allow for the empirical test of error estimates and determination of parameter degeneracies, via generation of many noise maps. The public release of this software, along with a large sample of cleaned COSMOS galaxy images (corrected for charge transfer inefficiency), should enable upcoming ground-based imaging surveys to achieve their potential in the areas of precision weak lensing analysis, galaxy profile measurement, and other applications involving detailed image analysis.

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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