34 citations · 88 across the 21 of their papers we have counts for
25 papers
NGC 3227 Blinks: An Extreme Changing-Look Event in a Seyfert Galaxy
Kaiwen Zhang, Michael S. Brotherton, Pu Du +10
We report a rapid optical changing-look event in the Seyfert galaxy NGC 3227: the optical continuum faded by more than 70% and broad H-beta emission nearly disappeared within weeks…
Cascade: GPU-Accelerated Out-of-Core Suffix Array Construction for LLM Corpora
Jamshed Khan, Prashant Pandey
Suffix arrays power deduplication, contamination testing, and training data attribution over the corpora used to train large language models, and must be rebuilt for every new corp…
On the Probability Distribution and Null-hypothesis Testing of Cross-correlation for Light Curves in Active Galactic Nuclei
Yan-Rong Li, Jian-Min Wang
Cross-correlation is crucial in studies of multiwavelength flux variability in active galactic nuclei (AGNs), especially for reverberation mapping analysis, where interpolated cros…
Nitrogen-Loud Quasars from the Dark Energy Spectroscopic Instrument. I. Sample Selection and Basic Properties
Shuo Zhai, Wei-Jian Guo, Yong-Jie Chen +4
We present the largest sample to date of nitrogen-loud (N-loud) quasars with strong broad N IV] and/or N III] emission lines over the redshift range $1.…
Observations of a Possible Transient Magnetically Arrested Accretion State in a Nearby Quasar: OQ208
Brian Punsly, Cormac Reynolds, Paola Marziani +12
OQ208 is a nearby, partially obscured quasar (z=0.077) that is a young, bright, parsec scale radio source. We assemble archival and new high frequency VLBA and VLA observations and…
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),…
Chemical evolution of bulges of active galactic nuclei in the early Universe: roles of accreting stars
Shuo Zhai, Jian-Min Wang, Yan-Rong Li +2
JWST/NIRCam observations reveal dense stellar cores in high-redshift galactic bulges, indicative of sustained star formation and potential stellar accretion. We introduce accretion…
Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. IV. Broad Emission Line Evolution Sequence Among Hα, Mg II, and Hβ
Wei-Jian Guo, Victoria A. Fawcett, Małgorzata Siudek +15
From a parent catalog of 561 changing-look active galactic nuclei (CL-AGNs) identified by Guo et al. (2025), we investigate the evolutionary sequence of broad emission lines using…
Little red dots as embryos of active galactic nuclei
Jian-Min Wang, Yi-Lin Wang, Yong-Jie Chen +7
As an unprecedented large population in the early universe, the JWST-discovered little red dots (LRDs) have garnered much attention for formation of massive black holes and galaxie…
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…
Spectroscopic Reverberation Mapping for SARM: The Case of Mrk 1048 and Mrk 618
Shivangi Pandey, Suvendu Rakshit, S. Muneer +14
Robust extragalactic distance measurements are crucial for resolving the persistent discrepancy in the value of the Hubble constant (H)). Active Galactic Nuclei (AGNs), through…
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…
Radial-dependent Responsivity of Broad-line Regions in Active Galactic Nuclei: Observational Consequences for Reverberation Mapping and Black Hole Mass Measurements
Yan-Rong Li, Jian-Min Wang
The reverberation mapping (RM) technique has seen wide applications in probing geometry and kinematics of broad-line regions (BLRs) and measuring masses of supermassive black holes…
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…
Geometrical Distances of Extragalactic Binaries through Spectroastrometry
Yu-Yang Songsheng, Jian-Min Wang, Yuan Cao +4
The growing ``Hubble tension'' has prompted the need for precise measurements of cosmological distances. This paper demonstrates a purely geometric approach for determining the dis…
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…
Bayesian synthesis of astrometric wobble and total light curves in close binary supermassive black holes
Andjelka B. Kovacevic, Yu-Yang Songsheng, Jian-Min Wang +1
We test the potential of Bayesian synthesis of upcoming multi-instrument data to extract orbital parameters and individual light curves of close binary supermassive black holes (CB…
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…
Spiral Arms in Broad-line Regions of Active Galactic Nuclei. I. Reverberation and Differential Interferometric Signals of Tightly Wound Cases
J. -M. Wang, P. Du, Y. -Y. Songsheng +1
As a major feature in spectra of active galactic nuclei, broad emission lines deliver information of kinematics and spatial distributions of ionized gas surrounding the central sup…
Search for Continuous Gravitational Wave Signals in Pulsar Timing Residuals: A New Scalable Approach with Diffusive Nested Sampling
Yu-Yang Songsheng, Yi-Qian Qian, Yan-Rong Li +5
Detecting continuous nanohertz gravitational waves (GWs) generated by individual close binaries of supermassive black holes (CB-SMBHs) is one of the primary objectives of pulsar ti…
Multi-Wavelength Monitoring and Reverberation Mapping of a Changing Look Event in the Seyfert Galaxy NGC 3516
V. L. Oknyansky, M. S. Brotherton, S. S. Tsygankov +26
We present the results of photometric and spectroscopic monitoring campaigns of the changing look AGN NGC 3516 carried out in 2018 to 2020 covering the wavelength range from the X-…
Dynamical evidence of the sub-parsec counter-rotating disc for a close binary of supermassive black holes in the nucleus of NGC 1068
J. -M. Wang, Y. -Y. Songsheng, Y. -R. Li +2
It arises a puzzle in \NGC\, how to secularly maintain the counter-rotating disc from to pc unambiguously detected by recent ALMA observations of molecular gas. Upon fur…
Constraining broad-line regions from time lags of broad emission lines relative to radio emission
H. T. Liu, J. M. Bai, J. M. Wang +1
In this paper, a new method is proposed to estimate the broad-line region sizes of UV lines . It is applied to 3C 273. First, we derive the time lags of rad…