发表机构
University of Delaware; Vera C. Rubin Observatory; University of North Carolina, Chapel Hill; California Institute of Technology（特拉华大学; 薇拉·C·鲁宾天文台; 北卡罗来纳大学教堂山分校; 加州理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用ZTF连续读出模式数据，结合深度学习流程，首次实现巡天规模的毫秒级光学瞬变搜索，未发现天体物理候选体，确立了光学短时标变率的稀有性。
AI 中文摘要
亚分钟时标相空间是光学天空中尚未充分探索的领域。传统的CCD曝光-读出循环难以实现亚秒级光学观测，而EMCCD和CMOS等替代技术历来将巡天限制在目标观测上。连续读出模式通过在读出期间保持快门开启，使传统相机能够进行毫秒级时标观测，从而实现在全天巡天中进行高频率观测。我们展示了来自兹威基瞬变设施（Zwicky Transient Facility）的连续读出模式数据的首批结果。我们开发了一套基于深度学习的数据分析流程，并报告了在141平方度（即1128星时）数据上的结果，采样率为每秒300次。我们的卷积神经网络（Convolutional Neural Network）能够检索持续时间为9.7至29.2毫秒的光学瞬变事件，对于10%及以上的亮度变化，其精确度为66%，召回率为78%；我们随后的基于光变曲线的分析效率超过94.6%。我们共检索到约30万个来自星等G_RP < 12的天体的候选事件，其中100个信噪比（SNR）高于1.55并经过了目视检查。在考虑噪声并过滤掉已知和该观测模式特有的污染物后，这100个候选事件均被排除为天体物理性质，从而对与点源以及白矮星和类星体相关的约10毫秒瞬变事件的观测速率给出了上限。这项首次巡天规模的亮毫秒光学瞬变和变源天空表征确立了光学波段短时标变率的稀有性。
英文摘要
The subminute-timescale phase space is an underexplored regime of the optical sky. Sub-second optical observations are difficult to accomplish with traditional CCD exposure-readout cycles, and alternative technologies like EMCCDs and CMOS have historically limited surveys to targeted observation. Continuous-readout mode enables millisecond-timescale observations on traditional cameras by leaving the shutter open during readout, enabling high-cadence observations on all-sky surveys. We present the first results from continuous-readout mode data from the Zwicky Transient Facility. We developed a deep-learning-based data analysis pipeline and report results on 141 square degrees, or 1128 star-hours, of data, sampled at 300x/second. Our Convolutional Neural Network can retrieve optical transients of duration 9.7-29.2 milliseconds with a precision of 66% and recall of 78% for brightness changes of 10% and greater, and our subsequent light curve-based analysis has an efficiency of >94.6%. We retrieve a total of ~300,000 candidates on sources of magnitude G_{RP} < 12, of which 100 are above SNR=1.55 and were visually inspected. After accounting for noise and filtering contaminants both known and unique to this mode of observation, these 100 candidates were eliminated as being astrophysical in nature, leading to upper limits on the observed rate of ~10-ms transient events associated with point sources as well as specifically with white dwarfs and quasars. This first survey-scale characterization of the bright millisecond optical transient and variable sky establishes the rarity of short-timescale variability in the optical regime.
CommentsSubmitted to PASP. 23 pages, 24 figures
