arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1402.2595astro-ph.HE
收藏

GRB 130427 A中的配对主导GeV-optical闪光

Pair-dominated GeV-optical flash in GRB 130427A

Indrek Vurm, Romain Hascoet, Andrei M. Beloborodov

摘要:

我们表明,在GRB 130427 A的双GeV+的光学闪光的光变曲线是一致的,从爆炸波的辐射在风型介质与密度参数$A=ρr^2\sim 5\times 10^{10}$ g cm $^{-1}$。闪光的峰值是由大量的$e^\pm$对产生和爆炸波加热,我们的第一原理计算确定的对加载因子和温度的冲击等离子体。使用详细的辐射转移模拟,我们重建所观察到的双闪光。光学闪光主要由前向激波后面的热等离子体的同步辐射所控制,GeV闪光是由相同的等离子体通过逆康普顿(IC)散射产生的。IC散射的种子光子主要是由即时MeV辐射在第一个几十秒,并由光学X射线余辉之后。IC冷却的热等离子体后面的前冲击再现所有GeV的数据从几秒钟到$\sim 1$天。我们发现在闪光峰值处的冲击波洛伦兹因子为$Γ\approx 200$,正向冲击磁化强度为$ε_B\sim 2\times 10^{-4}$。一个额外的来源是需要在光学和X射线波段的数据在时间$>10^2$ s,我们推测,这个额外的来源可能是一个长期的反向冲击在爆炸喷出物。

英文摘要:

We show that the light curve of the double GeV+optical flash in GRB 130427A is consistent with radiation from the blast wave in a wind-type medium with density parameter $A=ρr^2\sim 5\times 10^{10}$ g cm$^{-1}$. The peak of the flash is emitted by copious $e^\pm$ pairs created and heated in the blast wave; our first-principle calculation determines the pair-loading factor and temperature of the shocked plasma. Using detailed radiative transfer simulations we reconstruct the observed double flash. The optical flash is dominated by synchrotron emission from the thermal plasma behind the forward shock, and the GeV flash is produced via inverse Compton (IC) scattering by the same plasma. The seed photons for IC scattering are dominated by the prompt MeV radiation during the first tens of seconds, and by the optical to X-ray afterglow thereafter. IC cooling of the thermal plasma behind the forward shock reproduces all GeV data from a few seconds to $\sim 1$ day. We find that the blast wave Lorentz factor at the peak of the flash is $Γ\approx 200$, and the forward shock magnetization is $ε_B\sim 2\times 10^{-4}$. An additional source is required by the data in the optical and X-ray bands at times $>10^2$ s; we speculate that this additional source may be a long-lived reverse shock in the explosion ejecta.

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。

↑