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arXiv · 2404.12976

Insights from the Gaussian Processes Method for the FRB-associated X-ray Burst of SGR 1935+2154

Ruijing Tang·Dahai Yan·Haiyun Zhang·Qingchang Zhao·Lian Tao·Chengkui Li·Mingyu Ge·Xiaobo Li·Qianqing Yin·Ce Cai
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Abstract

Gaussian processes method is employed to analyze the light curves of bursts detected by Insight-HXMT, NICER, and GECAM from SGR 1935+2154 between 2020 to 2022. It is found that a stochastically driven damped simple harmonic oscillator (SHO) is necessary to capture the characteristics of the X-ray bursts. Variability timescale of the X-ray bursts, corresponding to the broken frequencies in the SHO power spectral densities (PSDs), are extracted. In particular, a high broken frequency of 35 Hz where the index of the SHO PSD changes from -4 to -2 is constrained by the HXMT-HE burst associated with FRB 200428. It is suggested that the corresponding timescale of 0.03 s could be the retarding timescale of the system driven by some energy release, and the production of the HE photon should be quasi-simultaneous with the response. The other special event is a NICER burst with a retarding timescale of 1/39 Hz (0.02 s). In the normal X-ray bursts, no retarding timescale is constrained; a long relax/equilibrium timescale (corresponding to a broken frequency of 1-10 Hz where the index of the SHO PSD changing from -4/-2 to 0 in the SHO PSD) is obtained. The results indicate that the FRB-associated HXMT-HE X-ray burst could be produced immediately when the system is responding to the energy disturbance, far before the equilibrium state.

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Ruijing Tang, Dahai Yan, Haiyun Zhang, Qingchang Zhao, Lian Tao, Chengkui Li, Mingyu Ge, Xiaobo Li, Qianqing Yin, Ce Cai. 2024-04-19. Insights from the Gaussian Processes Method for the FRB-associated X-ray Burst of SGR 1935+2154. https://arxiv.org/abs/2404.12976

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