AI 中文总结
本研究通过分析OCEANS、CEERS和RUBIES巡天数据，发现2个小红点（LRDs）存在Hα宽线变异性，为其活动星系核（AGN）性质提供了部分证据，该结果与典型类星体变异性存在约2σ偏离。
AI 中文摘要
小红点（Little Red Dots, LRDs）是詹姆斯·韦伯空间望远镜（JWST）河外深场中发现的一类独特的致密红色天体。确定它们是否确实由吸积超大质量黑洞（supermassive black holes, SMBHs）提供能量，是对这些天体开展密集研究的主要驱动因素之一。这类天体的变异性证据为其中心引擎是否属于活动星系核（active galactic nucleus, AGN）提供了直接检验。本研究对OCEANS巡天（分辨率R~2700）观测的6个LRDs开展变异性分析，并利用CEERS和RUBIES巡天存档的分辨率R~1000光谱数据。我们报告在LRDs OCEANS-100424/RUBIES-42232中检测到Hα宽线（broad-line, BL）变异性的边缘信号（变异性为27%，显著性为2.1σ），在OCEANS-35829/RUBIES-49140（GlimmIr/Irony）中检测到该信号（变异性为50%，显著性为1.5σ）。样本中其余4个LRDs未显示宽线变异性证据，其观测历元之间的变异性1σ上限为4.8%至30%。我们还发现LRDs样本中没有连续谱变异性的证据（<1σ）。我们将结果与SDSS-RM类星体样本进行比较，以确定Hα宽线变异性检测结果的概率，发现重现2个变异性和4个非变异性类星体的概率为4.71%，对应与典型类星体变异性约2σ的偏离。在2个LRDs中检测到Hα宽线变异性，为这些天体的AGN性质提供了部分证据，反对纯散射模型。
英文摘要
Little Red Dots (LRDs) are a unique class of compact, red sources discovered in the JWST extragalactic deep fields. Determining if they are indeed powered by accreting supermassive black holes (SMBHs) is one of the main drivers of the intense study of these objects. Evidence for variability in these objects provides a direct test for the active galactic nucleus (AGN) nature of their central engine. In this study, we present a variability analysis of 6 LRDs observed by the $R \sim 2700$ OCEANS survey and leverage archival $R \sim 1000$ spectroscopic data from the CEERS and RUBIES surveys. We report marginal detections of $\rm Hα$ broad-line (BL) variability in the LRDs OCEANS-100424/RUBIES-42232 (27\% variability at 2.1$σ$ significance) and OCEANS-35829/RUBIES-49140 (GlimmIr/Irony; 50\% variability at 1.5$σ$ significance). The other 4 LRDs in our sample do not show evidence for BL variability, with a 1$σ$ upper limit of $4.8 \% - 30\%$ variability between their epochs of observations. We also find no evidence ($<1σ$) for continuum variability in our LRD sample. We compare our results to a sample of SDSS-RM quasars to determine the probability of our broad $\rm Hα$ variability detections. We find that the probability of reproducing 2 variable and 4 nonvariable quasars is $4.71\%$, corresponding to $\sim 2 σ$ departure from typical quasar variability. The detection of BL $\rm Hα$ variability in 2 LRDs provides some evidence for the AGN nature of these objects as opposed to pure scattering models.
Comments19 pages, 8 figures, submitted to ApJ
