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arXiv 1605.09367astro-ph.HE
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Fermi-LAT GRB余辉的7.2/3年收集

The 7.2/3 Years Collection of Well-Monitored Fermi-LAT GRB Afterglows

A. Panaitescu

摘要:

我们提出的光变曲线和光谱的24余辉,已监测费米-LAT在0.1-100 GeV超过十年的时间。所有的光变曲线(除了130427)都符合一个单一的幂律从他们的峰值开始,这发生在大多数情况下,在爆发结束之前。光变曲线显示出亮度衰减率的相关性,除了一个(130427)明亮的余辉衰减速度快于较暗的余辉。我们将这种二分法归因于相对论喷出物能量在外部冲击中的快速沉积,用于较亮/较快衰减的余辉,以及用于较暗/较慢衰减的光变曲线的余辉冲击中的延长的能量注入。六种余辉的光谱(090328,100414,110721,110731,130427,140619 B)表明在能量为0.3-3 GeV的光谱凹陷/踝部上方存在较硬的分量,为更高能量下的逆康普顿发射提供了证据,这表明,其他五个LAT余辉的更硬的幂律谱(130327 B,131231,150523,150627,160509)也可能是逆康普顿,而其余较软的LAT余辉应该是同步加速器。边际证据的光谱断裂和软化在较高的能量被发现两个余辉(090902 B和090926)。

英文摘要:

We present the light-curves and spectra of 24 afterglows that have been monitored by Fermi-LAT at 0.1-100 GeV over more than a decade in time. All light-curves (except 130427) are consistent with a single power-law starting from their peaks, which occurred, in most cases, before the burst end. The light-curves display a brightness-decay rate correlation, with all but one (130427) of the bright afterglows decaying faster than the dimmer afterglows. We attribute this dichotomy to a quick deposition of the relativistic ejecta energy in the external-shock for the brighter/faster-decaying afterglows and to an extended energy-injection in the afterglow shock for the dimmer/slower-decaying light-curves. The spectra of six afterglows (090328, 100414, 110721, 110731, 130427, 140619B) indicate the existence of a harder component above a spectral dip/ankle at energy 0.3-3 GeV, offering evidence for an inverse-Compton emission at higher energies, and suggesting that the harder power-law spectra of five other LAT afterglows (130327B, 131231, 150523, 150627, 160509) could also be inverse-Compton, while the remaining softer LAT afterglows should be synchrotron. Marginal evidence for a spectral break and softening at higher energies is found for two afterglows (090902B and 090926).

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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