25 citations · 25 across the 6 of their papers we have counts for
8 papers · 1 filter
First Observational Evidence for QPO-like Coevolution between Characteristic Damping Timescales and X-ray Time Lags among AGNs
Haoyang Zhang, Li Zhang
Quasi-periodic oscillations (QPOs) and stochastic variability provide complementary probes of the inner accretion flow around supermassive black holes in active galactic nuclei (AG…
Detection of a puzzling dual-superorbital hard X-ray modulation in the X-ray binary GX 301-2
Haoyang Zhang, Li Zhang
The superorbital modulations (SMs) observed in wind-fed X-ray binaries remain a puzzling phenomenon in astrophysics. To investigate this behavior observationally, we analyzed the l…
Gaussian Process Modeling Coronal X-ray Variability of Active Galactic Nuclei
Haiyun Zhang, Dahai Yan, Li Zhang +1
The corona is an integral component of active galactic nuclei (AGNs) which can produce the X-ray emission. However, many of its physical properties and the mechanisms powering this…
Patterns of X-ray and -ray Flares: from Blazar to Maganetar and Sun
Haiyun Zhang, Dahai Yan, Lijuan Dong +6
Using Gaussian process methods, we analyzed the light curves of three extreme solar X-ray flares observed by the RHESSI satellite. Their variability characteristics were then compa…
Revisiting the observation-theory confrontation in high-frequency QPOs:a new QPO in NGC 5506, intermediate mass black holes, and the crucial role of accretion state
Haoyang Zhang, Lingwei Meng, Li Zhang +1
The scale invariance of accretion processes (SIAP) is crucial for understanding the physical processes of black hole accretion systems at different scales. When applying this rule…
Pattern and Origin for the Extreme -ray Flares of 3C 454.3 and 3C 279: An Astrophysical Critical Damper?
Haiyun Zhang, Dahai Yan, Jianeng Zhou +2
We apply a Gaussian process method to the extreme -ray flares of 3C 454.3 and 3C 279 to discover the variable patterns and then to investigate the physical origins of the giant…
Evidence for Magneto-gravitational Processes in Supermassive Black Hole Binary PG 1553+113
Haiyun Zhang, Dahai Yan, Li Zhang +1
PG1553+113 has drawn significant attention for its quasi-periodic oscillation (QPO) in gamma-ray variability, though the origin of its variability remains uncertain. In this study,…
Gaussian Process Modeling Blazar Multiwavelength Variability: Indirectly Resolving Jet Structure
Haiyun Zhang, Dahai Yan, Li Zhang
Blazar jet structure can be indirectly resolved by analyzing the multiwavelength variability. In this work, we analyze the long-term variability of blazars in radio, optical and X-…