arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1707.04592astro-ph.IM
收藏

局部双样本检验:一种分析高维天文数据的新工具

Local Two-Sample Testing: A New Tool for Analysing High-Dimensional Astronomical Data

P. E. Freeman, I. Kim, A. B. Lee

摘要:

现代调查为天文学界提供了大量的高维数据,但对这些数据的分析通常发生在将其投影到低维空间之后。在这项工作中,我们介绍了一个本地的两个样本的假设检验框架,分析师可以直接应用到他们的原生空间中的数据。在这个框架中,分析师定义了两个类的基础上的响应变量的兴趣(例如,高质量的星系与低质量的星系),并确定在任意点的预测空间是否属于两个类的对象的局部比例显着不同的全球比例。我们的框架在整个天文学中有潜在的无数用途;在这里,我们通过将其应用于HST ACS在四个CANDELS计划领域观察到的2487个i波段选择星系的样本来证明其有效性。对于每个星系,我们有七个形态的汇总统计数据,以及估计的恒星质量和恒星形成率。我们进行了两项研究:其中一个是我们确定的七维空间的形态统计区域,其中高质量的星系明显比低质量的星系多,反之亦然,另一项研究中,我们使用SFR的地方质量。我们发现,我们能够识别这样的区域,并显示如何高质量/低SFR区域与集中和不受干扰的星系,而在低质量/高SFR区域的星系出现更多的扩展和/或干扰比他们的高质量/低SFR同行。

英文摘要:

Modern surveys have provided the astronomical community with a flood of high-dimensional data, but analyses of these data often occur after their projection to lower-dimensional spaces. In this work, we introduce a local two-sample hypothesis test framework that an analyst may directly apply to data in their native space. In this framework, the analyst defines two classes based on a response variable of interest (e.g. higher-mass galaxies versus lower-mass galaxies) and determines at arbitrary points in predictor space whether the local proportions of objects that belong to the two classes significantly differs from the global proportion. Our framework has a potential myriad of uses throughout astronomy; here, we demonstrate its efficacy by applying it to a sample of 2487 i-band-selected galaxies observed by the HST ACS in four of the CANDELS program fields. For each galaxy, we have seven morphological summary statistics along with an estimated stellar mass and star-formation rate. We perform two studies: one in which we determine regions of the seven-dimensional space of morphological statistics where high-mass galaxies are significantly more numerous than low-mass galaxies, and vice-versa, and another study where we use SFR in place of mass. We find that we are able to identify such regions, and show how high-mass/low-SFR regions are associated with concentrated and undisturbed galaxies while galaxies in low-mass/high-SFR regions appear more extended and/or disturbed than their high-mass/low-SFR counterparts.

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。

↑