Beniamini, P. 2011 通过假设GeV和MeV光子的比例，来限制GeV的流量

主要内容:
通过假设GeV的能量是MeV的0.1，Le T., & Dermer C. D., 2009, ApJ, 700, 1026.他们得到过GeV的流量，不过和观测有些不符。

他们应该是用一个更加复杂一点的办法（没看明白，但大意应该是和上面类似），得到GeV辐射的上限，也就是给出二者比例的上限。这个上限还可以和观测到了GeV流量的暴比较，见下图，红色部分，都还吻合呢。

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Title:		Limits on the GeV Emission from Gamma-Ray Bursts
Authors:		Beniamini, P.; Guetta, D.; Nakar, E.; Piran, T.
Publication:		eprint arXiv:1103.0745
Publication Date:		03/2011
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena
Comment:		Accepted for publication in MNRAS
Bibliographic Code:		2011arXiv1103.0745N

Abstract

The Large Area Telescope (LAT) on board of the Fermi satellite detected emission above 30 MeV only in a small fraction of the long gamma-ray bursts (GRBs) detected by the Fermi Gamma-ray Burst Monitor (GBM) at 8 keV - 10 MeV. Those bursts that were detected by the LAT were among the brightest GBM bursts. We examine a sample of the most luminous GBM bursts with no LAT detection and obtain upper limits on their high energy fluence. We find an average upper limit of LAT/GBM fluence ratio of 0.13 for GeV fluence during $T_{90}$ and an average upper limit ratio of 0.45 for GeV fluence during the first 600 seconds after the trigger. These ratios strongly constrain various emission models and in particular rule out SSC models for the prompt emission. In about a third of both LAT detected and LAT non-detected bursts, we find that the extrapolation of the MeV range Band spectrum to the GeV range is larger than the observed GeV fluence (or its upper limit). While this excess is not highly significant for any specific burst, the overall excess in a large fraction of the bursts suggests a decline in the high energy spectral slope in at least some of these bursts. Possibly an evidence for the long sought after pair creation limit.

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