5 papers
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.…
Radio Activity Across Accretion State Changes in Changing-look AGNs: Insights from FIRST and VLASS over Two Decades
Zhi-Qiang Chen, Wei-Jian Guo, Victoria A. Fawcett +8
Changing-look active galactic nuclei (CL-AGNs) provide a unique opportunity to probe the coupling between accretion flows and relativistic jets in supermassive black holes. We inve…
Changing-look Active Galactic Nuclei from SDSS, LAMOST and DESI Surveys
Guohai Chen, Wenxin Yang, Xuhong Ye +4
Results. We identify 45 CLAGNs, of which 40 are newly reported. The sample is dominated by turn-off events, comprising 43 turn-off and 2 turn-on sources. This may be because Type 2…
Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. V. Dramatic Variability in High-Ionization Broad Emission Lines
Zhi-Qiang Chen, Jun-Jie Jin, Wei-Jian Guo +10
We present a systematic search for changing-look (CL) quasars at high redshift z > 0.9 by cross-matching the spectroscopic datasets from the Dark Energy Spectroscopic Instrument Da…
Gleeok's Fire-breathing: Triple Flares of AT 2021aeuk within Five Years from the Active Galaxy SDSS J161259.83+421940.3
Dong-Wei Bao, Wei-Jian Guo, Zhi-Xiang Zhang +12
We present a noteworthy transient AT 2021aeuk exhibiting three distinct optical flares between 2018 and 2023. It is hosted in a radio-loud narrow-line Seyfert 1 (NLSy1) galaxy, wit…