发表机构
Vanderbilt University Medical Center; KTH Royal Institute of Technology and Stockholm University; CERIST Constantine; Independent Researcher; Instituto de Astrofísica de Canarias（范德堡大学医学中心; 瑞典皇家理工学院和斯德哥尔摩大学; 康斯坦丁科学文化研究与调解研究中心; 独立研究者; 加那利群岛天体物理学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究对POSS-I巡天中107,875个历史光学瞬变事件进行地球投影聚类分析，通过两种独立方法识别出多个统计显著热点区域，并发现瞬变事件位置与核试验地点存在关联。
AI 中文摘要
帕洛马天文台巡天-I（POSS-I）在斯普特尼克号发射前获取的图像中包含与亚秒级闪光一致的星状点源，这些点源在后续所有观测中均未出现。这些瞬变事件的性质和起源至今仍知之甚少。基于表明它们处于地球同步轨道的模型，我们估算了POSS-I瞬变事件出现时的经纬度。从包含107,875个POSS-I瞬变事件的数据集中，我们根据机器学习模型筛选出一个具有高概率代表真实天体的子集。我们采用两种独立方法来检验瞬变事件是否在特定位置（热点区域）非随机聚集。通过将离散的5°×5°地球投影区域内的瞬变事件数量与这些区域内随机预期的数量进行比较，识别出16个统计显著的热点区域。另外，两步聚类分析识别出6个高度显著的热点区域（轮廓系数=0.70）。两种方法识别出几个相似的热点区域，这些区域不能归因于POSS-I巡天的偏差：1）墨西哥南部/中美洲以西的太平洋海域，2）墨西哥湾南部，3）美国西南部（亚利桑那州塞多纳、新墨西哥州白沙地区）。与已报告的瞬变事件-核试验关联相关的瞬变事件表现出位置特异性，在太平洋核试验期间瞬变事件位置完全位于太平洋，而在内华达州核试验期间则主要位于美国西南部。这些发现暗示了POSS-I瞬变事件具有引人入胜的特征。
英文摘要
Palomar Observatory Sky Survey-I (POSS-I) images obtained before the launch of Sputnik contain star-like point sources consistent with sub-second flashes that are absent from all subsequent observations. The nature and origin of these transients remain poorly understood. Based on models suggesting they are in geosynchronous orbit, we estimated the latitude/longitude over which POSS-I transients appeared. From a dataset of 107,875 POSS-I transients, we selected a subset with high probability of representing real objects based on a machine learning model. Two independent approaches were used to test whether transients non-randomly grouped over specific locations (hotspots). Based on comparing transient numbers in discrete 5° x 5° Earth-projected regions to numbers randomly expected in these same regions, 16 statistically-significant hotspots were identified. Separately, two-step cluster analysis identified 6 highly-distinct hotspots (silhouette value = 0.70). The two methods identified several similar hotspots not attributable to POSS-I survey biases: 1) Pacific ocean west of southern Mexico/Central America, 2) southern Gulf of Mexico, 3) southwestern US (Sedona, AZ, White Sands, NM regions). Transients accounting for reported transient-nuclear testing associations displayed location specificity, with exclusively Pacific transient locations during Pacific nuclear testing and primarily southwestern US locations during Nevada testing. Findings hint at intriguing POSS-I transient characteristics.
Comments34 pages, 2 figures
