Report
Transition from Fireball to Poynting-flux-dominated Outflow in Three-Episode GRB 160625B
| العنوان: | Transition from Fireball to Poynting-flux-dominated Outflow in Three-Episode GRB 160625B |
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| المؤلفون: | Zhang, B. -B., Zhang, B., Castro-Tirado, A. J., Dai, Z. G., Tam, P. -H. T., Wang, X. -Y., Hu, Y. -D., Karpov, S., Pozanenko, A., Zhang, F. -W., Mazaeva, E., Minaev, P., Volnova, A., Oates, S., Gao, H., Wu, X. -F., Shao, L., Tang, Q. -W., Beskin, G., Biryukov, A., Bondar, S., Ivanov, E., Katkova, E., Orekhova, N., Perkov, A., Sasyuk, V., Mankiewicz, L., Zarnecki, A. F., Cwiek, A., Opiela, R., Zadrozny, A., Aptekar, R., Frederiks, D., Svinkin, D., Kusakin, A., Inasaridze, R., Burhonov, O., Rumyantsev, V., Klunko, E., Moskvitin, A., Fatkhullin, T., Sokolov, V. V., Valeev, A. F., Jeong, S., Park, I. H., Caballero-Garcia, M. D., Cunniffe, R., Tello, J. C., Ferrero, P., Pandey, S. B., Jelinek, M., Peng, F. K., Sanchez-Ramirez, R., Castellon, A. |
| سنة النشر: | 2016 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - High Energy Astrophysical Phenomena |
| الوصف: | The ejecta composition is an open question in gamma-ray bursts (GRB) physics. Some GRBs possess a quasi-thermal spectral component in the time-resolved spectral analysis, suggesting a hot fireball origin. Others show a featureless non-thermal spectrum known as the "Band" function, consistent with a synchrotron radiation origin and suggesting that the jet is Poynting-flux-dominated at the central engine and likely in the emission region as well. There are also bursts showing a sub-dominant thermal component and a dominant synchrotron component suggesting a likely hybrid jet composition. Here we report an extraordinarily bright GRB 160625B, simultaneously observed in gamma-rays and optical wavelengths, whose prompt emission consists of three isolated episodes separated by long quiescent intervals, with the durations of each "sub-burst" being $\sim$ 0.8 s, 35 s, and 212 s, respectively. Its high brightness (with isotropic peak luminosity L$_{\rm p, iso}\sim 4\times 10^{53}$ erg/s) allows us to conduct detailed time-resolved spectral analysis in each episode, from precursor to main burst and to extended emission. The spectral properties of the first two sub-bursts are distinctly different, allowing us to observe the transition from thermal to non-thermal radiation between well-separated emission episodes within a single GRB. Such a transition is a clear indication of the change of jet composition from a fireball to a Poynting-flux-dominated jet. Comment: Revised version reflecting the referees' comments. 27 pages, 11 figures, 5 tables. The final edited version will appear in Nature Astronomy |
| نوع الوثيقة: | Working Paper |
| URL الوصول: | http://arxiv.org/abs/1612.03089 |
| رقم الانضمام: | edsarx.1612.03089 |
| قاعدة البيانات: | arXiv |
| الوصف غير متاح. |