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arXiv 1003.4250astro-ph.HE
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GRB 090902 B:余辉观测和意义

GRB 090902B: afterglow observations and implications

S. B. Pandey, C. A. Swenson, D. A. Perley, C. Guidorzi, K. Wiersema, D. Malesani, C. Akerlof, M. C. B. Ashley, D. Bersier, Z. Cano, A. Gomboc, I. Ilyin, P. Jako… 展开作者

S. B. Pandey, C. A. Swenson, D. A. Perley, C. Guidorzi, K. Wiersema, D. Malesani, C. Akerlof, M. C. B. Ashley, D. Bersier, Z. Cano, A. Gomboc, I. Ilyin, P. Jakobsson, I. K. W. Kleiser, S. Kobayashi, C. Kouveliotou, A. J. Levan, T. A. McKay, A. Melandri, C. J. Mottram, C. G. Mundell, P. T. O'Brien, A. Phillips, J. M. Rex, M. H. Siegel, R. J. Smith, I. A. Steele, G. Stratta, N. R. Tanvir, D. Weights, S. A. Yost, F. Yuan, W. Zheng

摘要:

LAT探测到的长持续时间爆发GRB 090902 B的光红外余辉已经被几种仪器观测到。ROTSE-IIIa最早的探测发生在费米伽马射线太空望远镜上的GBM仪器探测到80分钟后,揭示了一个明亮的余辉和一个衰变斜率,暗示了一个反向激波的起源。随后的光学-IR观察遵循光变曲线6.5天。在光学-红外频率的时间和光谱行为与同步加速器火球模型预测一致;冷却中断位于爆发后约1.9天的光学和XRT频率之间。推断的电子能量指数是$p = 1.8 \pm 0.2$,然而这意味着X射线衰变斜率比观察到的更平坦。XRT和LAT数据具有相似的光谱指数,并且观察到的LAT时间指数的陡峭值与前向冲击模型的辐射机制中的预测时间衰减略微一致。在最初的6天内没有喷流中断意味着经过准直校正的$γ$射线能量$E_γ > 2.2\times10^{52}\rm$ ergs,这是在长持续时间伽玛暴中看到的最高能量之一。将需要更多的事件结合GeV光子发射与多波长观测,以限制为这些高能爆炸提供动力的中央引擎的性质,并探索高能量子和余辉发射之间的相关性。

英文摘要:

The optical-infrared afterglow of the LAT-detected long duration burst, GRB 090902B, has been observed by several instruments. The earliest detection by ROTSE-IIIa occurred 80 minutes after detection by the GBM instrument onboard the Fermi Gamma-Ray Space Telescope, revealing a bright afterglow and a decay slope suggestive of a reverse shock origin. Subsequent optical-IR observations followed the light curve for 6.5 days. The temporal and spectral behavior at optical-infrared frequencies is consistent with synchrotron fireball model predictions; the cooling break lies between optical and XRT frequencies ~ 1.9 days after the burst. The inferred electron energy index is $p = 1.8 \pm 0.2$, which would however imply an X-ray decay slope flatter than observed. The XRT and LAT data have similar spectral indices and the observed steeper value of the LAT temporal index is marginally consistent with the predicted temporal decay in the radiative regime of the forward shock model. Absence of a jet break during the first 6 days implies a collimation-corrected $γ$-ray energy $E_γ > 2.2\times10^{52}\rm$ ergs, one of the highest ever seen in a long-duration GRBs. More events combining GeV photon emission with multi-wavelength observations will be required to constrain the nature of the central engine powering these energetic explosions and to explore the correlations between energetic quanta and afterglow emission.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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