arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1801.09183astro-ph.HE
收藏

了解GRB的即时排放机制:II。峰值能量演化模式及其与光谱滞后的联系

Toward an understanding of GRB prompt emission mechanism: II. Patterns of peak energy evolution and their connection to spectral lags

Z. Lucas Uhm, Bing Zhang, Judith Racusin

摘要:

伽马射线暴的瞬发相具有两种不同的峰值能量($E_p$)演化模式,即:宽脉冲的$νF_ν$谱的时间分辨谱分析揭示了$E_p$随时间演化的(1)“硬到软”和(2)“通量跟踪”模式,其物理起源仍然没有很好地理解。我们在这里表明,这两种模式可以成功地再现在一个简单的物理模型调用同步辐射在一个散装加速发射区。我们进一步表明,峰值能量的演变模式,事实上,直接连接到两个不同的(正或负)类型的光谱滞后的存在,看到在宽脉冲。特别地,我们预测:(1)对于峰值能量的硬到软演化,只有正类型的谱滞后是可能的,(2)在峰值能量的通量跟踪模式的情况下,正和负类型的谱滞后都可以发生,(3)对于通量跟踪模式,如果光谱滞后为正,则通量光曲线的峰值位置稍微滞后于随时间的$E_p$演化的峰值,以及(4)在通量跟踪图案的情况下,在光变曲线中可以出现双峰宽脉冲,其形状与能量有关。

英文摘要:

The prompt emission phase of gamma-ray bursts (GRBs) exhibits two distinct patterns of the peak-energy ($E_p$) evolution, i.e., time-resolved spectral analyses of $νF_ν$ spectra of broad pulses reveal (1) "hard-to-soft" and (2) "flux-tracking" patterns of $E_p$ evolution in time, the physical origin of which still remains not well understood. We show here that these two patterns can be successfully reproduced within a simple physical model invoking synchrotron radiation in a bulk-accelerating emission region. We show further that the evolution patterns of the peak energy have, in fact, direct connections to the existence of two different (positive or negative) types of spectral lags, seen in the broad pulses. In particular, we predict that (1) only the positive type of spectral lags is possible for the hard-to-soft evolution of the peak energy, (2) both the positive and negative type of spectral lags can occur in the case of flux-tracking pattern of the peak energy, (3) for the flux-tracking pattern, the peak location of the flux light curve slightly lags behind the peak of the $E_p$ evolution with time if the spectral lags are positive, and (4) in the case of flux-tracking pattern, double-peaked broad pulses can appear in the light curves, the shape of which is energy-dependent.

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。

↑