小波分析找周期的方法应用到一个QPO上

小波分析找周期的方法应用到一个QPO上

 arXiv:2209.10408 [pdf, other]

Wavelet analysis of the transient QPOs in MAXI J1535−571 with Insight-HXMT

X. Chen, W. Wang, P F. Tian, P. Zhang, Q. Liu, H. J. Wu, N. Sai, Y. Huang, L. M. Song, J. L. Qu, L. Tao, S. Zhang, F. J. Lu, S. N. Zhang

Comments: 10 pages, MNRAS in press

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)

Using wavelet analysis and power density spectrum, we investigate two transient quasi-periodic oscillations (QPOs) observed in MAXI J1535−571 observed with Insight-HXMT. The transient QPOs have a centroid frequency of ∼10 Hz with a FWHM ∼0.6 Hz and an rms amplitude ∼14%. Energy spectra of QPO and non-QPO regimes are also separated and analyzed, and the spectra become softer with higher Ecut in the non-QPO regime compared to the QPO regime. Our results suggest that the transient QPOs detected in MJD 58016 and 58017 are still the type-C QPO, and the source remains in its HIMS. The duration of all type-C QPO signals based on wavelet is positively correlated with the mean count rate above ∼10 keV, implying appearance of QPOs in different time scales should be coupled with the corona. The transient QPO properties could be related to the jet or flares, perhaps the partial ejection of the corona is responsible for the disappearance of the type-C QPO.

来源： https://arxiv.org/list/astro-ph/new

典型小波分析的图

整理出PDS, 可以看到10Hz的峰.

他们同一天还发了一篇另一个QPO的, miliHertz

arXiv:2209.10455 [pdf, other]

High energy Millihertz quasi-periodic oscillations in 1A 0535+262 with Insight-HXMT challenge current models

Ruican Ma, Lian Tao, Shuang-Nan Zhang, Long Ji, Liang Zhang, Qingcui Bu, Jinlu Qu, Pablo Reig, Mariano Méndez, Yanan Wang, Xiang Ma, Yue Huang, Mingyu Ge, Liming Song, Shu Zhang, Hexin Liu, Pengju Wang, Lingda Kong, Xiaoqin Ren, Shujie Zhao, Wei Yu, Zixu Yang, Panping Li, Shumei Jia

Comments: 13 pages, 7 figures. Accepted for publication in MNRAS

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

We studied the millihertz quasi-periodic oscillation (mHz QPO) in the 2020 outburst of the Be/X-ray binary 1A 0535+262 using Insight-HXMT data over a broad energy band. The mHz QPO is detected in the 27-120 keV energy band. The QPO centroid frequency is correlated with the source flux, and evolves in the 35-95 mHz range during the outburst. The QPO is most significant in the 50-65 keV band, with a significance of ~ 8 sigma, but is hardly detectable (<2 sigma) in the lowest (1-27 keV) and highest (>120 keV) energy bands. Notably, the detection of mHz QPO above 80 keV is the highest energy at which mHz QPOs have been detected so far. The fractional rms of the mHz QPO first increases and then decreases with energy, reaching the maximum amplitude at 50-65 keV. In addition, at the peak of the outburst, the mHz QPO shows a double-peak structure, with the difference between the two peaks being constant at ~0.02 Hz, twice the spin frequency of the neutron star in this system. We discuss different scenarios explaining the generation of the mHz QPO, including the beat frequency model, the Keplerian frequency model, the model of two jets in opposite directions, and the precession of the neutron star, but find that none of them can explain the origin of the QPO well. We conclude that the variability of non-thermal radiation may account for the mHz QPO, but further theoretical studies are needed to reveal the physical mechanism.