标题： 多年堆叠搜索太阳系天体 显示英文标题

标题： Multi-year stacking searches for solar system bodies

摘要： 数字跟踪通过沿假设轨道叠加多张图像来检测微弱的太阳系天体，从而揭示在每张单独曝光中无法检测到的天体。 以前的搜索仅限于小区域和短时间基线。 我们提出一个通用框架，以量化在多年时间基线上对全天空非线性运动进行数字跟踪的灵敏度和计算需求。 我们从匹配滤波叠加开始，并推导信噪比（SNR）如何随着试轨道不匹配而退化，这导致了轨道参数空间上的度量张量。 该度量定义了局部欧几里得坐标，在这些坐标中SNR损失是各向同性的，并且有一个协变密度，指定了为选定的SNR容差所需的试轨道数量。 我们使用Zwicky瞬变设施（ZTF）数据验证了该方法，在盲搜中恢复了已知天体，这些搜索沿着数十亿条试轨道在六年时间内叠加了数千张图像。 我们量化了ZTF对5天文单位以外天体种群的灵敏度，并表明叠加能够覆盖大部分剩余的第九行星参数空间。 全天区、多年跟踪的计算需求非常大，但我们证明时间分段和图像模糊可以在适度的灵敏度代价下大大降低轨道密度。 叠加有效地将中等孔径巡天提升到了鲁宾天文台单次曝光在北半球的深度。 在10平方度区域的密集鲁宾观测中进行数字跟踪是可行的，并且可以在一晚内检测到27等的海王星外天体，深度钻探场可以探测更暗的天体。 显示英文摘要

摘要： Digital tracking detects faint solar system bodies by stacking many images along hypothesized orbits, revealing objects that are undetectable in every individual exposure. Previous searches have been restricted to small areas and short time baselines. We present a general framework to quantify both sensitivity and computational requirements for digital tracking of nonlinear motion across the full sky over multi-year baselines. We start from matched-filter stacking and derive how signal-to-noise ratio (SNR) degrades with trial orbit mismatch, which leads to a metric tensor on orbital parameter space. The metric defines local Euclidean coordinates in which SNR loss is isotropic, and a covariant density that specifies the exact number of trial orbits needed for a chosen SNR tolerance. We validate the approach with Zwicky Transient Facility (ZTF) data, recovering known objects in blind searches that stack thousands of images over six years along billions of trial orbits. We quantify ZTF's sensitivity to populations beyond 5 au and show that stacking reaches most of the remaining Planet 9 parameter space. The computational demands of all-sky, multi-year tracking are extreme, but we demonstrate that time segmentation and image blurring greatly reduce orbit density at modest sensitivity cost. Stacking effectively boosts medium-aperture surveys to the Rubin Observatory single-exposure depth across the northern sky. Digital tracking in dense Rubin observations of a 10 sq. deg field is tractable and could detect trans-Neptunian objects to 27th magnitude in a single night, with deep drilling fields reaching fainter still.