2024/08/30 by Haifan Zhu, Wei Wang, Zhu, Haifan +3 · 1 citation
Earth and Planetary Sciences · Mathematics · Physics and Astronomy · #FOS: Physical sciences #Geophysics and Gravity Measurements #High Energy Astrophysical Phenomena (astro-ph.HE) #Statistical and numerical algorithms #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2408.17039
openalex publication_date 2024/08/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present the results of bicoherence analysis for Swift J1727.8-1613 during its 2023 outburst, using data from Insight-HXMT. Our analysis focused on observations with quasi-periodic oscillations (QPOs) of frequencies greater than 1 Hz, revealing that all of them belong to type C QPOs. We found a strong correlation between the QPO frequency and the hardness ratio, as well as a linear relationship between the QPO RMS and the hardness ratio. The bicoherence analysis revealed a transition from a "web" pattern to a "hypotenuse" pattern in the LE and HE energy bands. In the bicoherence patterns, there are correlations between horizontal and vertical bicoherence at f1=f2=f\rm QPO with count rates. The diagonal structure at f1+f2=f\rm QPO becomes more prominent with increasing energy. Additionally, we discovered a new bicoherence pattern in the medium energy band from 10 -- 20 keV, the diagonal structure at f1+f2=f\rm har is prominent only in this energy band, which we refer to as the "parallel" pattern. The bicoherence analysis indicates that the source is likely a low-inclination source.