Disk reverberation mapping of a handful of nearby AGN suggest accretion disk sizes which are a factor few too large for their luminosities, apparently at odds with the standard model. Here, we investigate the likely contribution to the measured delay signature of diffuse continuum emission arising from broad line region gas. We start by constructing spherically symmetric pressure-law BLR models (i.e., $P(r)\propto r^{-s}$) that approximately reproduce the observed emission line fluxes of the strong UV--optical emission-lines in the best-studied source, NGC~5548. We then determine the contribution of the diffuse continuum to the measured continuum flux and inter-band delays, accounting for the observed variability behaviour of the ionizing nuclear continuum. Those pressure-law models that approximately reproduce the observed emission-line luminosities unavoidably produce substantial diffuse continuum emission. This causes a significant contamination of the disk reverberation signature (i.e., wavelength-dependent continuum delays). Qualitatively, the diffuse continuum delay signatures produced by our models resemble that observed for NGC~5548, including the deviation of the lag spectrum above that of a simple power-law in wavelength, short-ward of the Balmer and Paschen jumps. Furthermore, for reasonable estimates of the BLR covering fraction, the delay induced by diffuse continuum emission causes elevated inter-band delays over the entire UV--optical regime; for these pressure-law models, there are no `disk-dominated' wavelength intervals. Thus, the diffuse continuum contribution must be taken into account in order to correctly infer AGN accretion disk sizes based on inter-band continuum delays.
Evidence of a diffuse, extended continuum source in quasars from the relative sizes of the broad line region and the UV-optical continuum source measured with microlensing
The UV/optical Continuum Reverberation Mapping of Eight Active Galactic Nuclei with Swift: Further Evidence for the Outer Component
Peking University（北京大学）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）；University of Illinois at Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）
The Sloan Digital Sky Survey Reverberation Mapping Project: Investigation of Continuum Lag Dependence on Broad-Line Contamination and Quasar Properties
Physically motivated AGN emissivity profiles and their effects on quasar microlensing signatures. 1. Multi-epoch accretion disc size inference
IFPU - Institute for Fundamental Physics of the Universe（基础物理宇宙研究所）；SISSA - International School for Advanced Studies（国际高等研究院）；INAF - Osservatorio Astronomico di Trieste（的里雅斯特天文台）；Center for Astrophysics and Cosmology, University of Nova Gorica（新戈里察大学天体物理学与宇宙学中心）
AGN Variability with Rubin Observatory in the 2030s
International Gemini Observatory/NSF NOIRLab（国际双子星天文台/美国国家光学红外天文实验室）；Heidelberg Institute for Theoretical Studies（海德堡理论研究所）；Departamento de Astronomia, Instituto de Física, Universidade Federal do Rio Grande do Sul（南里奥格兰德联邦大学物理学院天文学系）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学卡尔·格利夫天体物理学研究所）；Center for Theoretical Physics, Polish Academy of Sciences（波兰科学院理论物理中心）；Instituto de Astrofísica de Andalucía (IAA-CSIC)（安达卢西亚天体物理学研究所（西班牙高等科学研究委员会））；Istituto Nazionale di Astrofisica, Osservatorio di Padova（意大利国家天体物理研究所帕多瓦观测站）
Emission-Line and Continuum Reverberation Mapping of the NLS1 Galaxy WPVS 48
Institut für Astrophysik und Geophysik, Universität Göttingen（哥廷根大学物理与天体物理研究所）；Department of Physics, Faculty of Natural Sciences, University of Haifa（海法大学自然科学学院物理系）；Haifa Research Center for Theoretical Physics and Astrophysics, University of Haifa（海法大学海法理论物理与天体物理学研究中心）；Ruhr University Bochum, Faculty of Physics and Astronomy, Astronomical Institute (AIRUB)（波鸿鲁尔大学物理与天文学院天文研究所）；School of Physics & Astronomy and the Wise Observatory, Tel-Aviv University（特拉维夫大学物理与天文学院及怀斯天文台）
Broad line regions behind haze: Intrinsic shape of Br$γ$ line and its origin in a type-1 Seyfert galaxy
Kagoshima University, Graduate School of Science and Engineering（鹿儿岛大学理工学部）；Ehime University, Research Center for Space and Cosmic Evolution（爱媛大学宇宙演化研究中心）；Hokkaido University, Faculty of Science（北海道大学理学部）；Max Planck Institute for Extraterrestrial Physics（马克斯·普朗克地外物理研究所）；De La Salle University（德拉萨大学）；Kavli Institute for Astronomy and Astrophysics at Peking University（北京大学科维理天文与天体物理研究所）
Discovery of a Luminosity-dependent Continuum Lag in NGC 4151 from Photometric and Spectroscopic Continuum Reverberation Mapping
Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台）；Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences（中国科学院天体结构与演化重点实验室）；Center for Astronomical Mega-Science, Chinese Academy of Sciences（中国科学院天文大科学研究中心）；Key Laboratory of Radio Astronomy and Technology, Chinese Academy of Sciences（中国科学院射电天文与技术重点实验室）；Department of Astronomy, Xiamen University（厦门大学天文学系）；Institute of Space Sciences (ICE, CSIC)（空间科学研究所（IEE-CSIC））；Jeremiah Horrocks Institute, University of Central Lancashire（中央兰开夏大学杰里迈亚·霍罗克斯研究所）；School of Physics and Astronomy, Sun Yat-sen University（中山大学物理与天文学院）；CSST Science Center for the Guangdong-Hong Kong-Macau Greater Bay Area（粤港澳大湾区空间站科学中心）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台）
The unusually red delay spectrum of the low-mass black hole AGN NGC\,4051 as revealed by intensive continuum reverberation mapping with the Las Cumbres Observatory
Wayne State University（韦恩州立大学）；University of St Andrews（圣安德鲁斯大学）；Durham University（杜伦大学）；Spectral Sciences Inc.（光谱科学公司）；University of Johannesburg（约翰内斯堡大学）；University of California, Irvine（加州大学尔湾分校）；University of Leicester（莱斯特大学）
NGC 4051低质量黑洞的异常红色延迟光谱通过密集连续反照率测绘揭示，其i和z_s波段延迟显著超出预期，可能由尘埃reddening或连续贡献解释。
