arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1503.01131astro-ph.HE
收藏

伽马射线暴喷流:均匀的还是结构化的?

Gamma-ray burst jets: uniform or structured?

O. S. Salafia, A. Pescalli, F. Nappo, G. Ghisellini, G. Ghirlanda, R. Salvaterra, G. Tagliaferri

摘要:

伽马射线暴(GRB)喷注的结构对其瞬发和余辉发射特性有很大影响。通过研究不同的结构对亮度函数(LF)的影响,可以深入了解伽玛暴的未知结构:i)我们表明,($10^{46} < L_{\rm iso} < 10^{48}$ erg/s)和高(即用$L_{\rm iso} > 10^{50}$ erg/s)亮度GRB可以用唯一的LF来描述; ii)我们发现均匀射流(轴上和轴外观察)以及非常陡峭的结构射流(即,具有$s > 4$的$ε(θ) \propto θ^{-s}$)可以再现当前LF数据; iii)考虑到整个射流的排放(即包括温和相对论的贡献,离轴射流元件),我们发现,$E_{\rm iso}(θ_{\rm v})$(我们称这个量为"表观结构")可以与固有结构$ε(θ)$非常不同:特别地,具有高斯本征结构的射流具有更类似于幂律的表观结构。这为结构射流的准普适性假说开辟了新的视角。

英文摘要:

The structure of Gamma-Ray Burst (GRB) jets impacts on their prompt and afterglow emission properties. Insights into the still unknown structure of GRBs can be achieved by studying how different structures impact on the luminosity function (LF): i) we show that low ($10^{46} < L_{\rm iso} < 10^{48}$ erg/s) and high (i.e. with $L_{\rm iso} > 10^{50}$ erg/s) luminosity GRBs can be described by a unique LF; ii) we find that a uniform jet (seen on- and off-axis) as well as a very steep structured jet (i.e. $ε(θ) \propto θ^{-s}$ with $s > 4$) can reproduce the current LF data; iii) taking into account the emission from the whole jet (i.e. including contributions from mildly relativistic, off-axis jet elements) we find that $E_{\rm iso}(θ_{\rm v})$ (we dub this quantity "apparent structure") can be very different from the intrinsic structure $ε(θ)$: in particular, a jet with a Gaussian intrinsic structure has an apparent structure which is more similar to a power law. This opens a new viewpoint on the quasi-universal structured jet hypothesis.

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。

↑