Synchrotron self-Compton flaring of TeV blazars I. Linear electron cooling
Synchrotron self-Compton flaring of TeV blazars I. Linear electron cooling
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TeV 耀变体的同步加速器自康普顿耀斑 I. 线性电子冷却
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
C. Röken
中科院分区：
文献类型：
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作者：
R. Schlickeiser;C. Röken
现代地面空气切伦科夫望远镜灵敏度的极大提高，以及在较低频率下的灵敏通量测量，需要准确地阐述耀斑blazar的理论辐射模型。在这里，我们考虑了同步加速器自康普顿(SSC)过程引起的TeV耀斑。我们假设，在t=t0时刻，由于单能(E0)超相对论电子的瞬时注入，发射结中出现耀斑。超相对论电子均匀地注入到结的体积上，随后在磁场中受到线性同步辐射冷却，磁场的强度在相对论电子的时间演化过程中保持不变。产生的同步光子受到源中冷电子的多次汤姆逊散射，引起空间光子扩散。解析地确定了光厚和薄的同步辐射强度和发射结中的光子密度分布随频率和时间的变化。同步加速器光子充当SSC过程的目标光子，这是在光学薄的频率范围内使用逆康普顿截面的汤姆森近似计算的。结果表明，在所有频率和时间，同步辐射过程的光学厚部分对所产生的SSC强度的贡献可以忽略不计。由于高能TeV光子没有经历弹性多次康普顿散射，所以在计算SSC强度和能量通量分布时忽略了光子扩散的影响。在Ef=15.8b−1/3GeV处，从低光子能量下的∝E−1/4 S幂定律谱et≤Es≤Ef跃迁到∝E−2 S[1−(Es/E0)]。
The vast improvement of the sensitivity of modern ground-based air Cherenkov telescopes, together with the sensitive flux measurements at lower frequencies, requires accurate elaborations of the theoretical radiation models for flaring blazars. Here the flaring of TeV blazars due to the synchrotron-self Compton (SSC) process is considered. We assume that, at the moment t = t0, a flare in the emission knot occurs due to the instantaneous injection of monoenergetic (E0) ultrarelativistic electrons. The ultrarelativistic electrons are injected uniformly over the knot volume and at later times are subject to linear synchrotron radiation cooling in a magnetic field whose strength remains constant during the time evolution of the relativistic electrons.The generated synchrotron photons are subject to multiple Thomson-scattering off the cold electrons in the source giving rise to spatial photon diffusion. Optically thick and thin synchrotron radiation intensities and photon density distributions in the emission knot as functions of frequency and time are analytically determined. The synchrotron photons serve as target photons for the SSC process, which is calculated in the optically thin frequency range using the Thomson approximation of the inverse Compton cross section. It is shown that the optically thick part of the synchrotron radiation process provides a negligible contribution to the resulting SSC intensity at all frequencies and times.Because the high-energy TeV photons undergo no elastic multiple Compton scatterings, we neglect the influence of photon diffusion in the calculation of the SSC intensity and fluence distribution with energy. The SSC fluence exhibits a break at Ef = 15.8b −1/3 GeV from a ∝E −1/4 s -power law spectrum at lower photon energies Et ≤ Es ≤ Ef to a ∝E −2 s [1 − (Es/E0)