发表机构
SUPA Physics and Astronomy, University of St. Andrews（圣安德鲁斯大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究利用暗能量巡天数据对宇宙正午时期类星体进行宽带反响映射，通过PyROA分析36条光变曲线，探测到31个类星体的波段间时延，发现其光谱符合薄盘模型，并指出宽线区影响较小，为LSST未来研究提供方向。
AI 中文摘要
宽带反响映射为研究超大质量黑洞周围吸积流的结构提供了有力工具。类星体光谱的紫外区域尤其引人关注，因为它能够区分吸积盘和宽线区对本地宇宙类星体观测变异的相对贡献。对宇宙正午时期（$z\sim 1-2$）类星体的观测为探测不同种群中的紫外辐射提供了机会，这些类星体涵盖了广泛的黑洞质量和光度范围。在此，我们重新分析了暗能量巡天（DES）中$z\sim0.7-2$之间的36条多年类星体光变曲线，以提取波段间时延并分析其光谱能量分布。利用PyROA，我们能够同时拟合所有多年的观测数据和四个光学波段，显著提高了时延探测能力，因为该方法能够对季节间隙进行插值。我们在31/36个类星体中发现了稳健的波段间时延信号，表明大部分天体具有高爱丁顿比率。它们的光谱能量分布与几何薄盘$f_\nu\propto\lambda^{-1/3}$一致，整体谱斜率为$-0.28\pm0.02$。完整类星体样本在巴耳末跳变区域未显示过量，表明在高爱丁顿比率源中，宽线区对反响信号的影响可能较小，这与本地宇宙中某些活动星系核的记录相符。LSST有望观测这一红移范围内的数千个类星体，这将推动对高爱丁顿比率类星体紫外静止框架的详细研究，以考虑宽线区的贡献并正确推断盘的大小。
英文摘要
Broadband reverberation mapping provides a powerful tool to investigate the structure of the accretion flow around supermassive black holes. The ultraviolet region of the quasar spectrum is of particular interest, as it enables the disentanglement of the relative contributions from the accretion disc and the broad-line region to the observed variability of quasars in the local Universe. Observations of quasars at cosmic noon ($z\sim 1-2$) offer the opportunity to probe the UV emission across a diverse population, spanning a broad range of black hole masses and luminosities. Here we re-analysed the 36 multi-year quasar lightcurves from the Dark Energy Survey (DES) between $z\sim0.7-2$ to retrieve interband delays and analyse their spectral energy distribution. Using PyROA, we were able to fit all multiple years of observations and the four optical bands simultaneously, significantly improving the lag detection as this method is able to interpolate over the seasonal gaps. We find robust detections of interband delays in 31/36 quasars, suggesting high-Eddington ratios for a large fraction of objects. Their spectral energy distribution is consistent with a geometrically thin disk $f_ν\proptoλ^{-1/3}$, with an ensemble slope of $-0.28\pm0.02$. The full sample of quasars do not show excess around the Balmer jump region, suggesting the impact of the broad-line region to the reverberation signals in high-Eddington sources could be small as documented in some AGN in the local Universe. The prospect of LSST to observe thousands of quasars in this redshift range should motivate the detailed study of the UV-rest frame of high-Eddington quasars to account for the BLR contribution and properly infer disc sizes.
Comments11 pages, 10 figures, to be submitted to MNRAS, comments are welcomed
