The rise of multimessenger astronomy has brought with it the need to exploit all available data streams and learn more about the astrophysical objects that fall within its breadth. One possible avenue is the search for serendipitous optical/near-infrared counterparts of gamma-ray bursts (GRBs) and gravitational-wave (GW) signals, known as kilonovae. With surveys such as the Zwicky Transient Facility (ZTF), which observes the sky with a cadence of ∼3 d, the existing counterpart locations are likely to be observed; however, due to the significant amount of sky to explore, it is difficult to search for these fast-evolving candidates. Thus, it is beneficial to optimize the survey cadence for realtime kilonova identification and enable further photometric and spectroscopic observations. We explore how the cadence of wide field-of-view surveys like ZTF can be improved to facilitate such identifications. We show that with improved observational choices, e.g. the adoption of three epochs per night on a ∼ nightly basis, and the prioritization of redder photometric bands, detection efficiencies improve by about a factor of two relative to the nominal cadence. We also provide realistic hypothetical constraints on the kilonova rate as a form of comparison between strategies, assuming that no kilonovae are detected throughout the long-term execution of the respective observing plan. These results demonstrate how an optimal use of ZTF increases the likelihood of kilonova discovery independent of GWs or GRBs, thereby allowing for a sensitive search with less interruption of its nominal cadence through Target of Opportunity programs.

中文翻译：

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优化千新星的偶然检测：节奏和过滤器选择

多信使天文学的兴起带来了利用所有可用数据流并更多地了解其范围内的天体物理对象的需求。一种可能的途径是寻找伽马射线暴 (GRB) 和引力波 (GW) 信号的偶然光学/近红外对应物，称为千新星。通过诸如 Zwicky Transient Facility (ZTF) 之类的观测，它以 ∼3 d 的节奏观测天空，可能会观测到现有的对应位置；然而，由于要探索的天空量很大，很难找到这些快速发展的候选者。因此，优化测量节奏以进行实时千新星识别并实现进一步的光度和光谱观测是有益的。我们探索如何改进像 ZTF 这样的宽视场调查的节奏以促进这种识别。我们表明，随着观测选择的改进，例如每晚每晚采用三个时期，以及更红的光度带的优先级，检测效率相对于标称节奏提高了大约两倍。我们还提供了对千新星率的现实假设约束，作为策略之间比较的一种形式，假设在各个观测计划的长期执行过程中没有检测到千新星。这些结果表明，ZTF 的最佳使用如何增加独立于 GW 或 GRB 的千新星发现的可能性，从而允许通过 Target of Opportunity 计划进行敏感搜索，同时减少其名义节奏的中断。