169 citations · 453 across the 32 of their papers we have counts for
33 papers
A Decade-Scale Ionization Echo of Black-Hole Accretion in Galactic Nuclei
Wei-Jian Guo, Shuo Zhai, Chen Hu +16
Circumnuclear structures in active galactic nuclei respond to accretion variability over different spatial and temporal scales, but whether compact narrow-line gas responds on deca…
Mrk 382: A Narrow-line Seyfert 1 Galaxy with Recurrent X-ray State Transitions
Yanli Ai, Wenfeng Wen, Liming Dou +10
We report recurrent X-ray state transitions in the nearby narrow-line Seyfert~1 galaxy Mrk~382 using multi-epoch observations from \textit{Swift}, \textit{Chandra}, \textit{XMM-New…
AGN STORM 2. XII. Ground-Based Optical Photometry and Lag Measurements of Mrk 817
John W. Montano, Aaron J. Barth, Keith Horne +40
We present the ground-based imaging campaign and light curves of Markarian 817 as part of the multiwavelength monitoring program AGN STORM\,2. Observations were carried out over 1.…
Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. XV. Reverberation Mapping of Mg II Emission Lines
Hua-Rui Bai, Pu Du, Chen Hu +25
As the 15th paper in a series reporting on a large reverberation mapping (RM) campaign of super-Eddington accreting massive black holes (SEAMBHs) in active galactic nuclei (AGNs),…
Detection of unexpected leading delays in broad Hβ line reverberations in the quasar PHL 1092
Jian-Min Wang, Chen Hu, Yong-Jie Chen +12
Delayed reverberations of broad emission lines in response to optical continuum variations have been widely observed in active galactic nuclei (AGNs). They serve as a powerful tool…
A Composite Broad-Line Region in SDSS J1609+4902: a Double-Peaked Disk component and a Gaussian Component
Jiancheng Wu, Qingwen Wu, Chen Hu +6
The profiles of broad emission lines in active galactic nuclei (AGNs) provide critical insights into the geometry and kinematics of the broad-line region (BLR), which in turn influ…
Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. XIV. Long-Duration High-Cadence Reverberation Mapping Results for 11 PG Quasars
Chen Hu, Zhu-Heng Yao, Yong-Jie Chen +20
We report the results of a long-duration high-cadence reverberation mapping campaign of a second batch of 11 PG quasars using the 2.2m telescope at the Calar Alto Observatory. This…
Monitoring AGNs with H Asymmetry. V. Long-term Variation and Evolution of the Broad H Emission-Line Profiles
Feng-Na Fang, Pu Du, Michael S. Brotherton +40
The physical origins of the diverse emission-line asymmetries observed in the spectra of active galactic nuclei (AGNs) remain incompletely understood. Monitoring the temporal varia…
Spectroastrometry and Reverberation Mapping of Active Galactic Nuclei. II. Measuring Geometric Distances and Black Hole Masses of Four Nearby Quasars
Yan-Rong Li, Jinyi Shangguan, Jian-Min Wang +35
The geometric distances of active galactic nuclei (AGNs) are challenging to measure because of their exceptionally compact structure yet vast cosmic distances. A combination of spe…
B2 1308+326: a changing-look blazar or not?
Ashwani Pandey, Chen Hu, Jian-Min Wang +6
In our previous study, we identified a shift in the synchrotron peak frequency of the blazar B2 1308326 from 10 Hz to 10 Hz during a flare, suggesting it could…
AGN STORM 2: X. The origin of the interband continuum delays in Mrk 817
Hagai Netzer, Michael R. Goad, Aaron J. Barth +26
The local (z=0.0315) AGN Mrk 817, was monitored over more than 500 days with space-borne and ground-based instruments as part of a large international campaign AGN STORM 2. Here, w…
Broad-line Region of the Quasar PG 2130+099. II. Doubling the Size Over Four Years?
Zhu-Heng Yao, Sen Yang, Wei-Jian Guo +16
Over the past three decades, multiple reverberation mapping (RM) campaigns conducted for the quasar PG 2130+099 have exhibited inconsistent findings with time delays ranging from $…
Spectroastrometry and Reverberation Mapping (SARM) of Active Galactic Nuclei. I. The H Broad-line Region Structure and Black Hole Mass of Five Quasars
Yan-Rong Li, Chen Hu, Zhu-Heng Yao +18
We conduct a reverberation mapping (RM) campaign to spectroscopically monitor a sample of selected bright active galactic nuclei with large anticipated broad-line region (BLR) size…
AGN STORM 2: IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-ray Spectroscopy
Fatima Zaidouni, Erin Kara, Peter Kosec +45
We present the results of the XMM-Newton and NuSTAR observations taken as part of the ongoing, intensive multi-wavelength monitoring program of the Seyfert 1 galaxy Mrk 817 by the…
Monitoring AGNs with H Asymmetry. IV. First Reverberation Mapping Results of 14 AGNs
T. E. Zastrocky, Michael S. Brotherton, Pu Du +41
We report first-time reverberation mapping results for 14 AGNs from the ongoing Monitoring AGNs with H Asymmetry campaign (MAHA). These results utilize optical spectra obtained…
AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817
Jack M. M. Neustadt, Christopher S. Kochanek, John Montano +49
We fit the UV/optical lightcurves of the Seyfert 1 galaxy Mrk 817 to produce maps of the accretion disk temperature fluctuations resolved in time and radius. The maps are…
Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. XIII. Ultraviolet Time Lag of H Emission in Mrk 142
V. C. Khatu, S. C. Gallagher, K. Horne +17
We performed a rigorous reverberation-mapping analysis of the broad-line region (BLR) in a highly accreting () active galactic nucleus, Markarian 142 (…
AGN STORM 2: V. Anomalous Behavior of the CIV Light Curve in Mrk 817
Y. Homayouni, Gerard A. Kriss, Gisella De Rosa +49
An intensive reverberation mapping campaign on the Seyfert 1 galaxy Mrk817 using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) revealed significant vari…
XMM-Newton Observations of Two Archival X-ray Weak Type 1 Quasars: Obscuration Induced X-ray Weakness and Variability
Zijian Zhang, Bin Luo, W. N. Brandt +6
We report \hbox{XMM-Newton} observations of two examples of an unclassified type of \hbox{X-ray} weak quasars from the \citet{2020ApJ...900..141P} survey of \hbox{X-ray} weak quasa…
AGN STORM 2. IV. Swift X-ray and ultraviolet/optical monitoring of Mrk 817
Edward M. Cackett, Jonathan Gelbord, Aaron J. Barth +48
The AGN STORM 2 campaign is a large, multiwavelength reverberation mapping project designed to trace out the structure of Mrk 817 from the inner accretion disk to the broad emissio…
Strong and Rapid X-ray Variability of the Super-Eddington Accreting Quasar SDSS J081456.10+532533.5
Jian Huang, Bin Luo, W. N. Brandt +6
We report strong and rapid X-ray variability found from the super-Eddington accreting quasar SDSS J081456.10+532533.5 at . It has a black-hole mass of $2.7\times10^{7}{M_…
Revisiting Emission-Line Measurement Methods for Narrow-Line Active Galactic Nuclei
Viraja C. Khatu, Sarah C. Gallagher, Keith Horne +16
Measuring broad emission-line widths in active galactic nuclei (AGN) is not straightforward owing to the complex nature of flux variability in these systems. Line-width measurement…
AGN STORM 2. III. A NICER view of the variable X-ray obscurer in Mrk 817
Ethan R. Partington, Edward M. Cackett, Erin Kara +44
The AGN STORM 2 collaboration targeted the Seyfert 1 galaxy Mrk 817 for a year-long multiwavelength, coordinated reverberation mapping campaign including HST, Swift, XMM-Newton, NI…
AGN STORM 2: II. Ultraviolet Observations of Mrk817 with the Cosmic Origins Spectrograph on the Hubble Space Telescope
Y. Homayouni, Gisella De Rosa, Rachel Plesha +62
We present reverberation mapping measurements for the prominent ultraviolet broad emission lines of the active galactic nucleus Mrk817 using 165 spectra obtained with the Cosmic Or…