Aoi 2009 通过高能cutoff来看，模拟结果伽玛暴的罗仑兹因子可能没那么高

主要内容:
主要观点是假设每个内激波都产生一个power law+cutoff，不同的内激波的辐射的求和是一个broken power law+cutoff，同时最小的罗仑兹因子也没那么高。像080916C，可以只有600.

不过不知道他的这个低频部分的谱指数（也就是他的每个pulse的真实谱指数）和观测到的低频谱指数是否相等哦

精彩摘抄:


文章信息:

· Find Similar Abstracts (with default settings below)

· arXiv e-print (arXiv:0904.4878)

· References in the Article

·

· Translate This Page

Title:		Can we probe the Lorentz factor of gamma-ray bursts from GeV-TeV spectra integrated over internal shocks?
Authors:		Aoi, Junichi; Murase, Kohta; Takahashi, Keitaro; Ioka, Kunihito; Nagataki, Shigehiro
Publication:		eprint arXiv:0904.4878
Publication Date:		04/2009
Origin:		ARXIV
Keywords:		Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Extragalactic Astrophysics
Comment:		11 pages, 7 figures
Bibliographic Code:		2009arXiv0904.4878A

Abstract

We revisit the high-energy spectral cutoff originating from the electron-positron pair creation in the prompt phase of gamma-ray bursts (GRBs) with numerical and analytical calculations. We show that the conventional exponential cutoff should be drastically modified to a steepened power-law in practical observations that integrate emissions from different internal shocks. Since the steepening is tiny for observations, this "smearing" effect can generally reduce the previous estimates of the Lorentz factor of the GRB outflows. We apply our formulation to GRB 080916C, recently detected by the LAT detector on the Fermi satellite, and find that the minimum Lorentz factor can be ~600 (or even smaller values), which is below but consistent with the previous result of ~900. Observing the steepening energy (so-called "pair-break energy") is crucial to diagnose the Lorentz factor and/or the emission site in the future observations.

---

Bibtex entry for this abstract Preferred format for this abstract (see Preferences)