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Modelling the projected separation of microlensing events using systematic time-series feature engineering
Astronomy and Computing ( IF 2.5 ) Pub Date : 2021-03-10 , DOI: 10.1016/j.ascom.2021.100460
A. Kennedy , G. Nash , N.J. Rattenbury , A.W. Kempa-Liehr

Gravitational microlensing events have led to the discovery of more than 80 planets. In anticipation of the launch of the NASA Nancy Grace Roman Space Telescope, observations of gravitational microlensing events are expected to become much more numerous, and current manual techniques for their analysis will become insufficient. As a first step towards the automated estimated of microlensing event parameters, we present a workflow for identifying characteristics of light curves to estimate the projected separation from microlensing observations. We based this method on systematic time-series feature analysis of simulated light curves and validated it for a parameter space reduced to the planet–star separation. We determined a set of seven time-series features for making accurate predictions of the separation parameter. This reduced feature space of light curves serves as reliable input to both parametric and nonparametric regression models. Specifically, we validated a Random Forest regressor with respect to noise and data outages, which are common to current microlensing data, and found that the model is very robust. For this purpose, we created an empirical noise model from known microlensing events and introduced a model for simulating missing data due to data outages. Furthermore, we present an implementation of Bayesian Linear Regression on polynomial combinations of these seven light curve features, which computes probability distributions for recovered planet–star separations. The Random Forest and Bayesian Linear Regression regressors have an out-of-sample mean absolute error of 0.00057RE and 0.00110RE, respectively. The presented feature extraction workflow is expected to open new opportunities for mapping observed light curves to the large parameter space of microlensing events, which will be very useful for analysing the data from the Roman telescope mission.



中文翻译:

使用系统的时间序列特征工程对微透镜事件的预计分离进行建模

引力微透镜事件导致发现了80多个行星。预期将发射NASA南希·格雷斯罗马太空望远镜,引力微透镜事件的观测将变得越来越多,而目前用于其分析的手动技术将变得不足。作为朝着自动估计微透镜事件参数迈出的第一步,我们提出了一种工作流程,用于识别光曲线的特征,以估计与微透镜观测值之间的投影距离。我们基于对模拟光曲线进行系统时间序列特征分析的方法,并针对减少到行星-恒星分离的参数空间对它进行了验证。我们确定了一组七个时间序列特征,以对分离参数进行准确的预测。减少的光曲线特征空间可作为参数和非参数回归模型的可靠输入。具体而言,我们针对噪声和数据中断(这是当前微透镜数据常见的)验证了随机森林回归器,并发现该模型非常健壮。为此,我们根据已知的微透镜事件创建了经验噪声模型,并引入了一种用于模拟由于数据中断而导致的数据丢失的模型。此外,我们在这七个光曲线特征的多项式组合上给出了贝叶斯线性回归的实现,它计算了恢复的行星-恒星分离的概率分布。随机森林和贝叶斯线性回归回归器的样本外平均绝对误差为0.00057 我们针对噪声和数据中断(这是当前微透镜数据常见的)验证了随机森林回归器,并发现该模型非常健壮。为此,我们根据已知的微透镜事件创建了经验噪声模型,并引入了一种用于模拟由于数据中断而导致的数据丢失的模型。此外,我们在这七个光曲线特征的多项式组合上给出了贝叶斯线性回归的实现,它计算了恢复的行星-恒星分离的概率分布。随机森林和贝叶斯线性回归回归器的样本外平均绝对误差为0.00057 我们针对噪声和数据中断(这是当前微透镜数据常见的)验证了随机森林回归器,并发现该模型非常健壮。为此,我们根据已知的微透镜事件创建了经验噪声模型,并引入了一种用于模拟由于数据中断而导致的数据丢失的模型。此外,我们在这七个光曲线特征的多项式组合上给出了贝叶斯线性回归的实现,它计算了恢复的行星-恒星分离的概率分布。随机森林和贝叶斯线性回归回归器的样本外平均绝对误差为0.00057 我们根据已知的微透镜事件创建了经验噪声模型,并介绍了一种用于模拟由于数据中断而导致的数据丢失的模型。此外,我们在这七个光曲线特征的多项式组合上给出了贝叶斯线性回归的实现,它计算了恢复的行星-恒星分离的概率分布。随机森林和贝叶斯线性回归回归器的样本外平均绝对误差为0.00057 我们根据已知的微透镜事件创建了经验噪声模型,并引入了一个用于模拟由于数据中断而导致的数据丢失的模型。此外,我们在这七个光曲线特征的多项式组合上给出了贝叶斯线性回归的实现,它计算了恢复的行星-恒星分离的概率分布。随机森林和贝叶斯线性回归回归器的样本外平均绝对误差为0.00057[RE 和0.00110[RE, 分别。预期的特征提取工作流程将为将观察到的光曲线映射到微透镜事件的大参数空间提供新的机会,这对于分析罗马望远镜任务的数据将非常有用。

更新日期:2021-03-21
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