The Sloan Digital Sky Survey Reverberation Mapping Project: UV–Optical Accretion Disk Measurements with the Hubble Space Telescope
The Sloan Digital Sky Survey Reverberation Mapping Project: UV–Optical Accretion Disk Measurements with the Hubble Space Telescope
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DOI：
10.3847/1538-4357/ac478b
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
Y. Homayouni;Megan R. Sturm;J. Trump;K. Horne;C. Grier;Yue Shen;W. Brandt;G. F. Alvarez;P. Hall;L. Ho;J. I. Li;Mouyuan Sun;D. Schneider
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作者：
Y. Homayouni;Megan R. Sturm;J. Trump;K. Horne;C. Grier;Yue Shen;W. Brandt;G. F. Alvarez;P. Hall;L. Ho;J. I. Li;Mouyuan Sun;D. Schneider
我们给出了从0.24<；z<；0.85处八个类星体的紫外光混响映射(RM)观测得到的吸积盘结构测量结果。紫外线光度法来自两个周期的哈勃太空望远镜监测，伴随着拉斯坎布雷天文台网络和利物浦望远镜的多波段光学监测。这些目标是从斯隆数字巡天混响测绘项目样本中挑选出来的，其黑洞质量的可靠测量来自HβRM结果。我们使用标枪和CREAM方法测量了紫外线和各种光学格栅波段之间的显著滞后。我们使用这两种方法的显著滞后结果来用马尔科夫链蒙特卡罗方法来拟合吸积盘结构。我们研究了吸积盘作为盘归一化、温度标度和效率的函数。我们发现了巴尔默和铁II谱线在离散波长范围内发出弥漫星云的直接证据。我们还发现，我们最适合的圆盘颜色分布与Shakura&Sunyaev圆盘模型大致一致。我们将我们的紫外光滞后与从相同类星体的光学光学滞后中推断出的盘大小进行了比较，发现我们的结果与这些类星体来自更广泛群体中有限的高滞后子集的结果是一致的。因此，我们的结果与假设类星体的子集中存在较长的圆盘滞后的模型大体一致，例如，由于电离日冕的大小非零和/或磁场加热对圆盘响应的贡献。
We present accretion-disk structure measurements from UV–optical reverberation mapping (RM) observations of a sample of eight quasars at 0.24 < z < 0.85. Ultraviolet photometry comes from two cycles of Hubble Space Telescope monitoring, accompanied by multiband optical monitoring by the Las Cumbres Observatory network and Liverpool Telescopes. The targets were selected from the Sloan Digital Sky Survey Reverberation Mapping project sample with reliable black hole mass measurements from Hβ RM results. We measure significant lags between the UV and various optical griz bands using JAVELIN and CREAM methods. We use the significant lag results from both methods to fit the accretion-disk structure using a Markov Chain Monte Carlo approach. We study the accretion disk as a function of disk normalization, temperature scaling, and efficiency. We find direct evidence for diffuse nebular emission from Balmer and Fe ii lines over discrete wavelength ranges. We also find that our best-fit disk color profile is broadly consistent with the Shakura & Sunyaev disk model. We compare our UV–optical lags to the disk sizes inferred from optical–optical lags of the same quasars and find that our results are consistent with these quasars being drawn from a limited high-lag subset of the broader population. Our results are therefore broadly consistent with models that suggest longer disk lags in a subset of quasars, for example, due to a nonzero size of the ionizing corona and/or magnetic heating contributing to the disk response.