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arXiv 1709.09145astro-ph.HE
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用SWIFT和FERMI模拟长伽马射线暴的光度函数

Modelling the luminosity function of long Gamma Ray Bursts using SWIFT and FERMI

Debdutta Paul

摘要:

我使用了\emph{Swift}和\emph{Fermi}共同的长伽马射线暴(GRB)样本来重新推导米德相关的参数。这使我能够自洽地估计所有红移未知的爆发的伪红移。这是第一次从这两台仪器中获得如此大的伽马射线暴样本,无论是单独使用还是结合使用,来模拟长伽马射线暴光度函数。伽玛射线暴的形成率被建模为宇宙恒星的形成率和伽玛射线暴的形成效率为一个给定的恒星质量的产品。一个指数截止的幂律光度函数与$ν= 0.6$和$ L_b = 5.4 \times10^{52} \, \rm{erg.s^{-1}},$的数据拟合得相当好,并且不需要宇宙学演化。在幂律破缺的情况下,需要包含由$L_{b}\sim0.3\times10^{52}\left(1+z\right)^{2.90} \, \rm{erg.s^{-1}},$给出的破缺的急剧演化,并且GRB形成效率(退化到GRB的聚束因子)随着红移而降低,如$\propto\left(1+z\right)^{-0.80}.$。导出的模型,然后作为模板来预测的CZTI探测到的伽玛暴的分布上的\emph{AstroSat},作为红移和光度的函数。这表明,通过对少量CZTI伽玛暴的快速定位和红移测量,\emph{AstroSat}将有助于改善典型和特殊伽玛暴的统计。

英文摘要:

I have used a sample of long Gamma Ray Bursts (GRBs) common to both \emph{Swift} and \emph{Fermi} to re-derive the parameters of the Yonetoku correlation. This allowed me to self-consistently estimate pseudo redshifts of all the bursts with unknown redshifts. This is the first time such a large sample of GRBs from these two instruments are used, both individually and in conjunction, to model the long GRB luminosity function. The GRB formation rate is modelled as the product of the cosmic star formation rate and a GRB formation efficiency for a given stellar mass. An exponential cut-off powerlaw luminosity function fits the data reasonably well, with $ν= 0.6$ and $ L_b = 5.4 \times10^{52} \, \rm{erg.s^{-1}},$ and does not require a cosmological evolution. In the case of a broken powerlaw, it is required to incorporate a sharp evolution of the break given by $L_{b}\sim0.3\times10^{52}\left(1+z\right)^{2.90} \, \rm{erg.s^{-1}},$ and the GRB formation efficiency (degenerate up to a beaming factor of GRBs) decreases with redshift as $\propto\left(1+z\right)^{-0.80}.$ However it is not possible to distinguish between the two models. The derived models are then used as templates to predict the distribution of GRBs detectable by CZTI on board \emph{AstroSat}, as a function of redshift and luminosity. This demonstrates that via a quick localization and redshift measurement of even a few CZTI GRBs, \emph{AstroSat} will help in improving the statistics of GRBs both typical and peculiar.

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。

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