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arXiv 1111.2990astro-ph.HE
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长伽马射线暴的Collapsar模型的观测印记

An observational imprint of the Collapsar model of long Gamma Ray Bursts

Omer Bromberg, Ehud Nakar, Tsvi Piran, Re'em Sari

摘要:

Collapsar模型为长伽马射线暴(GRB)和坍缩大质量恒星之间的联系提供了一个理论框架。一个双极的相对论性喷流,从坍缩恒星的核心发射,在产生观测到的伽马射线之前,穿过恒星的外壳,冲出表面。虽然大量的观测将伽玛暴与大质量恒星的死亡联系在一起,但到目前为止还没有直接的证据来支持Collapsar模型本身。在这里,我们表明,一个独特的签名的Collapsar模型是一个高原的出现在时间比典型的突破时间的射流的即时伽玛射线暴发射的持续时间分布。这一平台在所有三颗主要卫星的数据中都很明显。这些发现提供了直接支持Collapsar模型的证据。此外,它表明存在大量的窒息(失败)的伽玛暴和2秒的持续时间通常用于分离Collapsar和非Collapsar是不一致的持续时间分布{ \it斯威夫特}和费米伽玛暴,只适用于BATSE伽玛暴。

英文摘要:

The Collapsar model provides a theoretical framework for the well known association between long gamma-ray bursts (GRBs) and collapsing massive stars. A bipolar relativistic jet, launched at the core of a collapsing star, drills its way through the stellar envelope and breaks out of the surface before producing the observed gamma-rays. While a wealth of observations associate GRBs with the death of massive stars, as yet there is no direct evidence for the Collapsar model itself. Here we show that a distinct signature of the Collapsar model is the appearance of a plateau in the duration distribution of the prompt GRB emission at times much shorter than the typical breakout time of the jet. This plateau is evident in the data of all three major satellites. These findings provide an evidence that directly supports the Collapsar model. Additionally, it suggests the existence of a large population of choked (failed) GRBs and that the 2 s duration commonly used to separate Collapsars and non-Collapasars is inconsistent with the duration distributions of {\it Swift} and Fermi GRBs and only holds for BATSE GRBs.

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