发表机构
California Institute of Technology; NSF-DOE Vera C. Rubin Observatory（加州理工学院; NSF-DOE薇拉·C·鲁宾天文台）
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LSST数据识别亚分钟级瞬变事件，发现其源于轨道碎片闪光，提出用双望远镜视差法区分本地与天体源，以探测真正的宇宙光学爆发。
AI 中文摘要
使用1米级望远镜的研究现已确定，卫星和空间碎片的闪光是对亚分钟级光学瞬变搜索的主要障碍。在此，我们报告了一项利用维拉·C·鲁宾天文台西蒙尼8.4米望远镜进行的时空遗产调查（LSST）观测来研究这一前景的工作。从2955对连续的30秒曝光中，覆盖了4755平方度的独特天区和472平方度小时的面积-时间覆盖，我们识别出了一类微弱的、类PSF的亚分钟事件，包括没有指示翻滚卫星的重复闪光线性序列（轨迹）的孤立事件。我们将这类事件的测量扩展到了迄今探测到的最暗星等，发现其发生率的下限为$(9.55 \n \pm 0.14) \times10^6\\,天空^{-1}\\,天^{-1}$，对应约23星等（中位数约22.3星等）。西蒙尼8.4米望远镜的大口径提供了额外的判别能力：低地球轨道上的轨道碎片由于散焦足够严重而被滤除。我们发现，对于1角秒的PSF，未分辨的事件被限制在距离超过1732公里处，并识别出了一类先前未报告的闪光，其与中地球轨道高度一致，估计尺寸约为1-3毫米。我们还报告了两个沿地球阴影深处视线观测到的孤立事件，对于这些事件，阳光照射碎片的起源不被支持。这些稀少的证据与食双星和恒星耀斑一致。对于亚分钟级瞬变，稳健的前进方向是由两个（或更多）相距甚远的望远镜同时观测同一视场。由此产生的视差测量将干净地消除局部（主要是轨道）碎片，阐明这一瞬变前景的本质。这一理解将帮助天文学家探测真正的地球外光学爆发。
英文摘要
Studies with 1-m class telescopes have now established that glints from satellites and space debris are the main obstacles to searches for sub-minute optical transients. Here, we report a study of this foreground using observations from the Legacy Survey of Space and Time (LSST) with the Simonyi 8.4-m telescope at the Vera C. Rubin Observatory. From 2,955 pairs of consecutive 30-s exposures, spanning 4,755 deg$^2$ of unique sky area and an area-time coverage of 472 deg$^2$ hr, we identified a population of faint, PSF-like, sub-minute events, including isolated events with no linear sequences of repeated flashes (tracklets) indicative of a tumbling satellite. We extended measurements of this population to the faintest magnitudes yet probed, finding a lower-bound to the occurrence rate of $(9.55 \pm 0.14) \times10^6\,$sky$^{-1}\,$day$^{-1}$ to $\sim23$ mag (median of $\sim22.3$ mag). The large aperture of the Simonyi 8.4-m telescope provides an additional discriminator: orbital debris in low-Earth orbit are sufficiently out of focus that they are filtered out. We find that, for a $1^{\prime\prime}$ PSF, unresolved events are constrained to distances beyond 1,732 km, and identify a previously unreported population of glints consistent with medium-Earth-orbit altitudes with estimated sizes of order $\sim1$-3 mm. We also report two isolated events observed along sight lines deep within the Earth's shadow, for which a sunlit-debris origin is disfavored. The scant evidence is consistent with an eclipsing binary and a stellar flare. The robust way forward for sub-minute transients is simultaneous observations of the same field by two (or more) widely separated telescopes. The resulting measurement of parallax will cleanly eliminate local (primarily orbital) debris, clarifying the nature of this transient foreground. This understanding will help astronomers probe truly celestial optical bursts.
Comments19 pages, 8 figures
