Photospheric Emission in Gamma-Ray Bursts. I. Variability

Wang, Kai; Lin, Da-Bin; Wang, Yun; Jiang, Lu-Yao; Du, Shen-Shi; Li, Xiaoyan; Ren, Jia; Wang, Xiang-Gao; Liang, En‐Wei

doi:10.3847/1538-4357/aba120

Cited by 5 publications

(3 citation statements)

References 61 publications

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“…Since the observed probability P of a photon is related to the optical depth τ for photons from their location to an observer, i.e., P ∝ exp(−τ ), a power-law distribution of temperature for mBB may be not well describe the contribution of the emission from different radius of the jet. By fitting the radiation spectrum of the photosphere from numerical calculation (e.g., Deng & Zhang 2014;Wang et al 2020), we point out the temperature distribution of the mBB used to well describe the photospheric emission may be…”

Section: Spectra Modeling Of a Non-dissipated Photospheric Emissionmentioning

confidence: 99%

Fermi Observations of GRB 220426A: a burst similar to GRB 090902B

Deng¹,

Lin²,

Li³

et al. 2022

Preprint

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We report on a very bright, long-duration gamma-ray burst (GRB), GRB 220426A, observed by Fermi satellite. GRB 220426A with total duration of T 90 = 6 s is composed with two main pulses and some sub-peaks. The spectral analysis of this burst with Band function reveals that both the time-integrated and the time-resolved spectra are very narrow with high α 0.2 and low β −3.1. It is strong reminiscent of GRB 090902B, a special GRB with identification of the photospheric emission. Then, we perform the spectral analysis of this burst based on a non-dissipated photospheric emission, which can be well modelled as the multicolor-blackbody with a cutoff power-law distribution of the thermal temperature. The spectral fittings reveal that the photospheric emission can well describe the radiation spectrum of this burst. We conclude that this burst would be a second burst in the class of GRB 090902B observed by Fermi satellite. We also discuss the physics of photosphere and the origin of the high-energy component in GRB 220426A .

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Section: Spectra Modeling Of a Non-dissipated Photospheric Emissionmentioning

confidence: 99%

Fermi Observations of GRB 220426A: a burst similar to GRB 090902B

Deng¹,

Lin²,

Li³

et al. 2022

Preprint

Self Cite

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“…Indeed, based on the spectral analysis, a quasi-thermal component has been found in several Fermi GRBs, particularly in GRB 090902B (Abdo et al 2009;Ryde et al 2010). But whether the typical observed Band function (smoothly joint broken power law; Band et al 1993) or cutoff power law (CPL) can be explained by the photosphere emission, namely the photosphere emission model, remains unknown (Abramowicz et al 1991;Thompson 1994;Rees & Mészáros 2005;Fan et al 2012;Lazzati et al 2013;Gao & Zhang 2015;Li et al 2019;Acuner et al 2020;Li 2020;Wang et al 2020;Jiang et al 2021;Meng 2022;Song & Meng 2022;Parsotan & Lazzati 2022;Vereshchagin et al 2022;Vyas & Pe'er 2023;Zhang et al 2023;Ito et al 2024). If this scenario is true, the quasi-thermal spectrum should be broadened.…”

Section: Introductionmentioning

confidence: 99%

Significant Cocoon Emission and Photosphere Duration Stretching in GRB 211211A: A Burst from a Neutron Star−Black Hole Merger

Meng,

Wang,

Liu

2024

ApJ

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The radiation mechanism (thermal photosphere or magnetic synchrotron) and the progenitor of gamma-ray bursts (GRBs) are under hot debate. Recently discovered, the prompt long-duration (∼10 s, normally from the collapse of massive stars) property of GRB 211211A strongly conflicts with its association with a kilonova (normally from the merger of two compact objects, NS–NS, NS–BH, or NS–WD, duration ≲2 s). In this paper, we find that the probability photosphere model with a structured jet can satisfactorily explain this peculiar long duration, through the duration stretching effect (∼3 times) on the intrinsic longer (∼3 s) duration of an NS–BH merger, the observed empirical 2SBPL spectrum (with soft low-energy index α of ∼−1), and its evolution. In addition, much evidence of the NS–BH merger origin is found, especially the good fit of the afterglow-subtracted optical−near-IR light curves by the significant thermal cocoon emission and the sole thermal “red” kilonova component. Finally, a convincing new explanation for the X-ray afterglow plateau is revealed.

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“…Indeed, based on the spectral analysis, a quasi-thermal component has been found in several Swift GRBs (Ryde 2004(Ryde , 2005Ryde & Pe'er 2009) and Fermi GRBs (Guiriec et al 2011(Guiriec et al , 2013Axelsson et al 2012;Ghirlanda et al 2013;Larsson et al 2015), especially in GRB 090902B (Abdo et al 2009;Ryde et al 2010;Zhang 2011). But whether the typical observed Band function (smoothly joint broken power law) (Band et al 1993) or cutoff power law can be explained by the photosphere emission, namely the photospheric emission model, remains unknown (e.g., Abramowicz et al 1991;Thompson 1994;Mészáros & Rees 2000;Rees & Mészáros 2005;Pe'er & Ryde 2011;Fan et al 2012;Lazzati et al 2013;Ruffini et al 2013;Gao et al 2015;Bégué & Pe'er 2015;Pe'er et al 2015;Ryde et al 2017;Acuner & Ryde 2018;Hou et al 2018;Meng et al 2018Meng et al , 2019Meng et al , 2022Li 2019aLi ,c, 2020Acuner et al 2020;Dereli-Bégué et al 2020;Vereshchagin & Siutsou 2020;Wang et al 2020;Parsotan & Lazzati 2022;Song & Meng 2022). If this scenario is true, the quasi-thermal spectrum should be broadened.…”

Section: Introductionmentioning

confidence: 99%

Evidences of the Photosphere Emission Origin for the Gamma-ray Burst Prompt Emission

Meng¹

2022

Preprint

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The physical origin of gamma-ray burst (GRB) prompt emission is still subject to debate after five decades (photosphere or synchrotron). Here, firstly we find that many observed characteristics of 15 long GRBs, which have the highest prompt emission efficiency γ ( γ 80%), strongly support the photosphere (thermal) emission origin: (1) The relation between E p and E iso is almost, and the dispersion is quite small. (2) The simple power-law shape of the X-ray afterglow light curves and the significant reverse shock signals in the optical afterglow light curves. (3) Best-fitted by the cutoff power-law model for the time-integrated spectrum. (4) The consistent efficiency from observation (with E iso /E k ) and the prediction of photosphere emission model (with η/Γ). Then, we further investigate the characteristics of the long GRBs for two distinguished samples ( γ 50% and γ 50%). It is found that the different distributions for E p and E iso , and the similar observed efficiency (from the X-ray afterglow) and theoretically predicted efficiency (from the prompt emission or the optical afterglow) well follow the prediction of photosphere emission model. Also, based on the same efficiency, we derive an excellent correlation of Γ ∝ E 1/8 iso E 1/2 p /(T 90 ) 1/4 to estimate Γ. Finally, the different distributions for E p and E iso , and the consistent efficiency exist for the short GRBs. Besides, we give a natural explanation of the extended emission ( γ 50%) and the main pulse ( γ 50%).

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Photospheric Emission in Gamma-Ray Bursts. I. Variability

Cited by 5 publications

References 61 publications

Fermi Observations of GRB 220426A: a burst similar to GRB 090902B

Fermi Observations of GRB 220426A: a burst similar to GRB 090902B

Significant Cocoon Emission and Photosphere Duration Stretching in GRB 211211A: A Burst from a Neutron Star−Black Hole Merger

Evidences of the Photosphere Emission Origin for the Gamma-ray Burst Prompt Emission

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