4 papers
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…
X-ray variability of SDSS J000532.84+200717.4: from a normal state to an X-weak state
Xiaohui Yang, Yanli Ai, Liming Dou +8
We present a multi-epoch study of the extreme X-ray variability of the type~1 quasar SDSS~J000532.84+200717.4 using archival observations from \textit{XMM-Newton}, \textit{Swift}/X…
Finding Quasars behind the Galactic Plane. IV. Candidate Selection from Chandra with Random Forest
Xu Zhang, Yanli Ai, Yanxia Zhang +8
Quasar samples remain severely incomplete at low Galactic latitudes because of strong extinction and source confusion. We conduct a systematic search for quasars behind the Galacti…
Highly Variable Quasar Candidates Selected from 4XMM-DR13 with Machine Learning
Heng Wang, Yanli Ai, Yanxia Zhang +6
We present a sample of 12 quasar candidates with highly variable soft X-ray emission from the 4th XMM-newton Serendipitous Source Catalog (4XMM-DR13) using random forest. We obtain…