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| Main Authors: | , , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2507.16538 |
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| _version_ | 1866915404726665216 |
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| author | Li, Guo-Yu Lin, Da-Bin Chen, Zhi-Lin Huang, Bao-Quan Liu, Tong Liang, En-Wei |
| author_facet | Li, Guo-Yu Lin, Da-Bin Chen, Zhi-Lin Huang, Bao-Quan Liu, Tong Liang, En-Wei |
| contents | Using data from Swift-BAT and Fermi-GBM, we report the first detection of a high-confidence quasi-periodic oscillation (QPO) in the thermal emission of gamma-ray burst GRB~240825A. The spectral analysis of the burst reveals two radiation components, including a thermal emission dominant in $100 \text{--} 300\,\mathrm{keV}$ and a non-thermal emission spanning a wide energy range. During the interval $2.07 \text{--} 3.25\,\mathrm{s}$ post-trigger, a strong QPO signal at $6.37\,\mathrm{Hz}$ ($\gtrsim 5σ$ confidence) is identified in the $100 \text{--} 300\,\mathrm{keV}$ thermal-dominated band. The variability analysis of the non-thermal component ($15 \text{--} 30\,\mathrm{keV}$) uncovered a $0.67\,\mathrm{Hz}$ QPO, consistent with light-curve modeling using periodic fast-rise exponential decay pulses. The strong QPO in the photospheric emission directly indicates a quasi-periodic oscillating jet. Together with the non-thermal emission variability, we show that this QPO can be explained in terms of a helical structure in the jet, where the viewing angle to the dominant emission region in the jet undergoes periodic changes. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_16538 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A $6.37\,{\rm Hz}$ quasi-periodic oscillating photospheric emission in GRB~240825A Li, Guo-Yu Lin, Da-Bin Chen, Zhi-Lin Huang, Bao-Quan Liu, Tong Liang, En-Wei High Energy Astrophysical Phenomena Using data from Swift-BAT and Fermi-GBM, we report the first detection of a high-confidence quasi-periodic oscillation (QPO) in the thermal emission of gamma-ray burst GRB~240825A. The spectral analysis of the burst reveals two radiation components, including a thermal emission dominant in $100 \text{--} 300\,\mathrm{keV}$ and a non-thermal emission spanning a wide energy range. During the interval $2.07 \text{--} 3.25\,\mathrm{s}$ post-trigger, a strong QPO signal at $6.37\,\mathrm{Hz}$ ($\gtrsim 5σ$ confidence) is identified in the $100 \text{--} 300\,\mathrm{keV}$ thermal-dominated band. The variability analysis of the non-thermal component ($15 \text{--} 30\,\mathrm{keV}$) uncovered a $0.67\,\mathrm{Hz}$ QPO, consistent with light-curve modeling using periodic fast-rise exponential decay pulses. The strong QPO in the photospheric emission directly indicates a quasi-periodic oscillating jet. Together with the non-thermal emission variability, we show that this QPO can be explained in terms of a helical structure in the jet, where the viewing angle to the dominant emission region in the jet undergoes periodic changes. |
| title | A $6.37\,{\rm Hz}$ quasi-periodic oscillating photospheric emission in GRB~240825A |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2507.16538 |