标题： LIGO/Virgo/KAGRA 中子星合并候选体 S250206dm：Zwicky 瞬变设施观测 显示英文标题

标题： LIGO/Virgo/KAGRA neutron star merger candidate S250206dm: Zwicky Transient Facility observations

摘要： 我们介绍了利用兹维基瞬变探测器 (ZTF) 针对 S250206dm 事件进行的搜寻。S250206dm 事件是国际引力波网络 (IGWN) 探测到的真实事件，其误报率为 25 年一次。 尽管该事件意义重大，但所涉及的致密天体的性质仍不清楚，至少有一颗疑似中子星。 ZTF 覆盖了 68% 的定位区域，但我们并未发现任何可能的光学对应体。 我们描述了 ZTF 的策略、潜在候选天体以及有助于排除候选天体的观测结果，包括其他合作项目传播的观测数据。 与 Ahumada 等人的研究类似， 2024 年，我们使用 simsurvey 进行频率学分析，并使用 nimbus 进行贝叶斯分析，以量化我们的搜寻效率。 我们发现，鉴于与该事件的标称距离为373百万秒差距（104 Mpc），对于绝对星等高于-17.5的千新星（KNe），我们的效率超过10%。 假设被称为千新星（KN）的光学对应体位于ZTF区域内，我们的极限限制了KN参数空间的最亮端。 通过对双中子星（BNS）和黑洞-中子星（BHNS）并合的KNe进行专门的辐射传输模拟，我们排除了部分BNS KN参数空间。 当正面观测（$\cos\theta_{\rm obs} = 1.0$）时，高达35%的高风喷射物质量（$M_{\rm wind} \approx 0.13$ M$_{\odot}$）的模型被排除。 最后，我们利用 ZTF 和引力波多信使暗能量相机巡天 (GW-MMADS) 的综合覆盖范围进行了联合分析。 联合观测覆盖了 73% 的局部化区域，并且联合效率对上升和缓慢衰减的模型影响更大，使我们能够排除 55% 正面观测到的高质量 KN 模型。 显示英文摘要

摘要： We present the searches conducted with the Zwicky Transient Facility (ZTF) in response to S250206dm, a bona fide event with a false alarm rate of one in 25 years, detected by the International Gravitational Wave Network (IGWN). Although the event is significant, the nature of the compact objects involved remains unclear, with at least one likely neutron star. ZTF covered 68% of the localization region, though we did not identify any likely optical counterpart. We describe the ZTF strategy, potential candidates, and the observations that helped rule out candidates, including sources circulated by other collaborations. Similar to Ahumada et al. 2024, we perform a frequentist analysis, using simsurvey, as well as Bayesian analysis, using nimbus, to quantify the efficiency of our searches. We find that, given the nominal distance to this event of 373$\pm$104 Mpc, our efficiencies are above 10% for KNe brighter than $-17.5$ absolute magnitude. Assuming the optical counterpart known as kilonova (KN) lies within the ZTF footprint, our limits constrain the brightest end of the KN parameter space. Through dedicated radiative transfer simulations of KNe from binary neutron star (BNS) and black hole-neutron star (BHNS) mergers, we exclude parts of the BNS KN parameter space. Up to 35% of the models with high wind ejecta mass ($M_{\rm wind} \approx 0.13$ M$_{\odot}$) are ruled out when viewed face-on ($\cos\theta_{\rm obs} = 1.0$). Finally, we present a joint analysis using the combined coverage from ZTF and the Gravitational Wave Multimessenger Dark Energy Camera Survey (GW-MMADS). The joint observations cover 73% of the localization region, and the combined efficiency has a stronger impact on rising and slowly fading models, allowing us to rule out 55% of the high-mass KN models viewed face-on.