Observations of the X-ray Millihertz Quasiperiodic Oscillations in Hercules X-1

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Hauptverfasser: Yang, Wen, Wang, Wei
Format: Preprint
Veröffentlicht: 2025
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author Yang, Wen
Wang, Wei
author_facet Yang, Wen
Wang, Wei
contents With a systematic timing investigation of the persistent X-ray binary pulsar Her X-1 based on a large number of Insight-HXMT observations between 2017 to 2019, we confirm the presence of X-ray millihertz quasi-periodic oscillations (mHz QPOs) at $\sim 0.01$ Hz. By applying wavelet analysis in our data analysis procedures, we firstly identified $\sim 0.005-0.009$ Hz QPOs coexisting with the $\sim 0.01$ Hz QPOs. Wavelet analysis suggests that these QPO features show transient behaviors, frequencies of mHz QPOs evolved in short time scales. There exists a positive relation between QPO centroid frequency (from $\sim 0.005-0.009$ Hz) and the X-ray luminosity, while the 10 mHz QPO frequencies keep nearly constant for different luminosities, which suggests different physical mechanisms for two types of mHz QPOs. The 10 mHz QPOs in both X-ray and UV bands would have the same origin related to the beat frequency where the Alfv$\acute{e}$n radius is close to the corotation radius, and the 5 mHz QPOs may originate from magnetic disk precession.
format Preprint
id arxiv_https___arxiv_org_abs_2501_15366
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Observations of the X-ray Millihertz Quasiperiodic Oscillations in Hercules X-1
Yang, Wen
Wang, Wei
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
With a systematic timing investigation of the persistent X-ray binary pulsar Her X-1 based on a large number of Insight-HXMT observations between 2017 to 2019, we confirm the presence of X-ray millihertz quasi-periodic oscillations (mHz QPOs) at $\sim 0.01$ Hz. By applying wavelet analysis in our data analysis procedures, we firstly identified $\sim 0.005-0.009$ Hz QPOs coexisting with the $\sim 0.01$ Hz QPOs. Wavelet analysis suggests that these QPO features show transient behaviors, frequencies of mHz QPOs evolved in short time scales. There exists a positive relation between QPO centroid frequency (from $\sim 0.005-0.009$ Hz) and the X-ray luminosity, while the 10 mHz QPO frequencies keep nearly constant for different luminosities, which suggests different physical mechanisms for two types of mHz QPOs. The 10 mHz QPOs in both X-ray and UV bands would have the same origin related to the beat frequency where the Alfv$\acute{e}$n radius is close to the corotation radius, and the 5 mHz QPOs may originate from magnetic disk precession.
title Observations of the X-ray Millihertz Quasiperiodic Oscillations in Hercules X-1
topic High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2501.15366