GRB相对论性外流的动力学和发射参数角分布的确定
Determination of the Angular Distributions of Dynamical and Emission Parameters of GRB Relativistic Outflows
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中文总结 AI 辅助
本研究扩展了大角度发射模型以包含磁场方向效应，应用于七个GRB，确定了核心参数Gamma_c*theta_c约为3.0，并发现磁场方向影响光变曲线曲率，其中平行磁场从未在核心中识别出。
中文摘要 AI 辅助
先前开发的用于伽马射线暴（GRB）及其余辉的“大角度发射”（LAE）模型的解析处理方法得到进一步发展，以纳入固定磁场方向的影响。该模型具有非凡的能力，能够统一瞬时发射和延迟发射，并轻松解释Swift X射线光变曲线的全部多样性。LAE模型被应用于七个GRB（060526、060614、060714、060729、061007、061121、100902、130427A），这些GRB具有采样良好的0.3 keV/10 keV Swift/XRT和光学光变曲线，显示出良好监测的四个阶段（GRB、尾、平台、平台后），以展示其能力和局限性，并确定其五个基本参数。唯一的核心参数Gamma_c*theta_c由GRB和余辉的时间里程碑（即由尾和平台的动力学范围）决定，可能具有约3.0的普适值，较窄的核心（较小的theta_c）更具相对论性（较高的Gamma_c）。平坦的平台要求包层角结构接近Gamma(theta) ~ 1/theta^2。平行于相对论性流方向的磁场产生的瞬时/GRB和延迟/余辉光变曲线比垂直或各向同性磁场产生的光变曲线更弯曲，曲率Δα定义为每个阶段开始和结束时通量渐近幂律衰减指数之差。来自均匀核心的GRB光变曲线的曲率Δα_grb仅由磁场方向决定，垂直或各向同性磁场出现的频率相同，但从未识别出核心的平行磁场。来自幂律包层的余辉光变曲线的曲率Δα_ag取决于磁场方向和其他三个参数。包层的磁场方向仅能对三个余辉进行识别，其中发现平行磁场。
英文摘要
A previously-developed analytical treatment of the "Larger-Angle Emission" model for GRBs and afterglows is further developed to include the effect of a fixed magnetic field orientation. This model, has the uncanny ability to unify the prompt and delayed emissions and to account easily for the entire diversity of Swift X-ray light-curves. The LAE model is applied to seven GRBs (060526, 060614, 060714, 060729, 061007, 061121, 100902, 130427A) with well-sampled 0.3 keV/10 keV Swift/XRT and optical light-curves, displaying well-monitored four phases (GRB, Tail, Plateau, post-Plateau), to illustrate its power and limitations and to determine its five fundamental parameters. The one-and-only Core parameter Gamma_c*theta_c is determined by the GRB and afterglow temporal milestones (i.e. by the dynamical range of the Tail and Plateau), and may have an universal value around 3.0, with narrower Cores (smaller theta_c) being more relativistic (higher Gamma_c). Flat Plateaus require an Envelope angular structure close to Gamma(theta) ~ 1/theta^2. A magnetic field parallel to the direction of the relativistic flow yields more curved prompt/GRB and delayed/afterglow light-curves than a perpendicular or isotropic field, with curvature $Δα$ defined as the difference between the flux asymptotic power-law decay indices at the beginning and end of each phase. The curvature Delta alpha_grb of the GRB light-curves arising from the uniform Core is set only by the B-field orientation, and a perpendicular or isotropic B-field is equally often found, but a parallel field is never identified for the Core. The curvature Delta alpha_ag of the afterglow light-curves from the power-law Envelope depends on B-orientation and three other parameters. The Envelope B-field orientation can be identified for only three afterglows, where a parallel B is found.
