论文标题
由电子在伽马射线爆发中的电子冷却引起的低能频谱
The Synchrotron Low-Energy Spectrum Arising from the Cooling of Electrons in Gamma-Ray Bursts
论文作者
论文摘要
这项工作是以前的努力（Panaitescu 2019）的延续，以研究通过辐射（同步加速器和自我孔子）的发射和绝热损失的相对论电子冷却，并应用了这种冷却电子产生的同步体gamma-ray爆发的光谱和光壳。在这里，我们得出了GRB脉冲集成频谱的低能斜率B_LE，并量化了B_LE测量分布的含义。 如果磁场的寿命比冷却GRB电子辐射到1-10 KEV以下，则使用N GEQ 2的辐射冷却过程，即通过NGEQ 2（即同步和逆）（IC）通过Thomson散射，导致柔和的低效光子slope beplope b_le le qulb_le le qulbe le qulbe le qulbe le qulle les qull pulcepry pulcep-1/1/1/1/ EPS^{b_le}下面的峰值E_P下方，无论电子注入t_i的持续时间如何。 IC冷却以E_P低于E_P的同步子光子的Thomson-Klein-Nishina转变为主导的IC冷却，其索引n = 2/3-> 1，并在[0,1/6]中与B_LE产生更硬的集成光谱，而在[0,1/6]中，将获得绝热的电子冷 - 冷却导线，向软slope b_le = -3/4。 仅当磁场寿命寿命t_b比典型的GRB电子散发到1-10 KEV以下的磁场寿命短时，才能容纳由CGRO/BATSE和FERMI/GBM测量的较难的斜率，而在1-10 KEV以下，该磁场寿命较短，这比（最多在最多）十个辐射散热的时机t _ y rak of smpectical of smpectical of of of syme of syme of of the offerative。在这种情况下，T_B和B_LE之间有一对一的对应关系。为了说明低能斜率B_LE> -3/4，绝热电子冷却需要对T_B的类似限制。在这种情况下，斜率的多样性主要源于电子注射速率随时间而不是磁场时间尺度的变化。
This work is a continuation of a previous effort (Panaitescu 2019) to study the cooling of relativistic electrons through radiation (synchrotron and self-Compton) emission and adiabatic losses, with application to the spectra and light-curves of the synchrotron Gamma-Ray Burst produced by such cooling electrons. Here, we derive the low-energy slope b_LE of GRB pulse-integrated spectrum and quantify the implications of the measured distribution of b_LE. If the magnetic field lives longer than it takes the cooling GRB electrons to radiate below 1-10 keV, then radiative cooling processes of power P(gamma) ~ gamma^n with n geq 2, i.e. synchrotron and inverse-Compton (iC) through Thomson scatterings, lead to a soft low-energy spectral slope b_LE leq -1/2 of the GRB pulse-integrated spectrum F_eps ~ eps^{b_LE} below the peak-energy E_p, irrespective of the duration of electron injection t_i. IC-cooling dominated by scatterings at the Thomson--Klein-Nishina transition of synchrotron photons below E_p has an index n = 2/3 -> 1 and yield harder integrated spectra with b_LE in [0,1/6], while adiabatic electron-cooling leads to a soft slope b_LE = -3/4. Radiative processes that produce soft integrated spectra can accommodate the harder slopes measured by CGRO/BATSE and Fermi/GBM only if the magnetic field life-time t_B is shorter than the time during which the typical GRB electrons cool to radiate below 1-10 keV, which is less than (at most) ten radiative cooling timescales t_rad of the typical GRB electron. In this case, there is a one-to-one correspondence between t_B and b_LE. To account for low-energy slopes b_LE > -3/4, adiabatic electron-cooling requires a similar restriction on t_B. In this case, the diversity of slopes arises mostly from how the electron-injection rate varies with time and not from the magnetic field timescale.
