Basak, Rupal 2013 高能GeV和MeV的幂律成分相关
主要内容:
他们把MeV的分成两种成分：黑体（双温）+幂律；然后发现幂律成分的光变和GeV瞬时阶段的光变一致（注意不是晚期的，他们还是同意晚期的还是外激波的同步辐射）(另外注意，这一点不是他们文章的主要内容，而是进一步的目标，他们发现的仅仅是：对于有很多GeV光子的暴，幂律的MeV光子和LAT的GeV光子一样，也有延迟，见下图)，以此说明瞬时阶段的辐射和瞬时阶段的幂律的MeV是同源的。
那么这么说的话，一共就有如下这些成分：瞬时的两个黑体成分，可能是来自光球辐射（为什么是两个呢？） ；瞬时幂律成分，来自内激波，这个延伸到了GeV；外激波余辉，延伸到了GeV。
于是紧接着可以做的一件事情：分析幂律MeV光子和瞬时阶段的GeV光子的光变曲线的关联程度（但是估计很难，因为不知道怎么在光变上区分幂律和非幂律的光子）。
嗯，也许把MeV的分出几个不同的成分是解释GeV以及MeV自身的一个办法。
精彩摘抄:
幂律部分的MeV光子应该和GeV的track
文章信息:
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| Title: | A lingering non-thermal component in the GRB prompt emission: predicting GeV emission from the MeV spectrum | |
| Authors: | Basak, Rupal; Rao, A. R. | |
| Publication: | eprint arXiv:1308.2819 | |
| Publication Date: | 08/2013 | |
| Origin: | ARXIV | |
| Keywords: | Astrophysics - High Energy Astrophysical Phenomena | |
| Comment: | 9 Pages, 2 Figures, ApJ Accepted | |
| Bibliographic Code: | 2013arXiv1308.2819B |
Abstract
The high energy GeV emission of gamma-ray bursts (GRBs), detected by \emph{Fermi}/LAT, has a significantly different morphology compared to the lower energy MeV emission, detected by \emph{Fermi}/GBM. Though the late time GeV emission is believed to be synchrotron radiation produced via an external shock, this emission as early as the prompt phase is puzzling. Meaningful connection between these two emissions can be drawn only by an accurate description of the prompt MeV spectrum. We perform a time-resolved spectroscopy of the GBM data of long GRBs having significant GeV emission, using a model consisting of 2 blackbodies and a power-law. We examine in detail the evolution of the spectral components and found that GRBs having high GeV emission (GRB 090902B and GRB 090926A) have a delayed onset of the power-law component, in the GBM spectrum, which lingers at the later part of the prompt emission. This behaviour mimics the flux evolution in LAT. In contrast, bright GBM GRBs with an order of magnitude lower GeV emission (GRB 100724B and GRB 091003) show a coupled variability of the total and the power-law flux. Further, by analyzing the data for a set of 17 GRBs, we find a strong correlation between the power-law fluence in the MeV and the LAT fluence (Pearson correlation: r=0.88 and Spearman correlation: $\rho=0.81$). We demonstrate that this correlation is not influenced by the correlation between the total and the power-law fluences at a confidence level of 2.3$\sigma$. We speculate the possible radiation mechanisms responsible for the correlation.Bibtex entry for this abstract Preferred format for this abstract (see Preferences)
