STUDY OF FOUR YOUNG TeV PULSAR WIND NEBULAE WITH A SPECTRAL EVOLUTION MODEL
STUDY OF FOUR YOUNG TeV PULSAR WIND NEBULAE WITH A SPECTRAL EVOLUTION MODEL
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DOI：
10.1088/0004-637x/741/1/40
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发表时间：
2011-08
期刊：
影响因子：
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通讯作者：
S. Tanaka;F. Takahara
中科院分区：
文献类型：
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作者：
S. Tanaka;F. Takahara
我们使用我们在之前的工作中开发并应用于蟹状星云的光谱演化模型，研究了在TeV γ射线中检测到的四个年轻脉冲星风星云（PWNe）：G21.5−0.9、G54.1+0.3、Kes 75和G0.9+0.1。考虑到脉冲星的时间依赖性注入以及辐射和绝热损失，我们对均匀扩展的 PWN 内的磁场和粒子分布函数的演化进行了建模。考虑到星际辐射场（ISRF）及其距离的不确定性，我们对每个 PWN 研究两种情况。由于 TeV PWNe 具有较大的 TeV γ 射线与 X 射线通量比，因此 PWNe 的磁能仅占注入总能量的一小部分（通常为几个 × 10−3）。 γ 射线发射主要是 ISRF 红外光子的逆康普顿散射。注入粒子的破坏幂律分布函数很好地再现了观察到的光谱（G0.9+0.1 除外）。对于 G0.9+0.1，我们不需要低能量对应物，因为仅绝热损失就足以再现射电观测结果。注入时的高能幂律指数相似（2.5-2.6），而低能幂律指数范围为 1.0 至 1.6。粒子注入速率的下限表明粒子对重数大于104。脉冲星风的体洛伦兹因子相应的上限接近破幂律注入的破断能，除了Kes 75。脉冲星的初始旋转能和磁能似乎是反相关的，尽管统计结果很差。
We study four young pulsar wind nebulae (PWNe) detected in TeV γ-rays, G21.5−0.9, G54.1+0.3, Kes 75, and G0.9+0.1, using the spectral evolution model developed and applied to the Crab Nebula in our previous work. We model the evolution of the magnetic field and the particle distribution function inside a uniformly expanding PWN considering a time-dependent injection from the pulsar and radiative and adiabatic losses. Considering uncertainties in the interstellar radiation field (ISRF) and their distance, we study two cases for each PWN. Because TeV PWNe have a large TeV γ-ray to X-ray flux ratio, the magnetic energy of the PWNe accounts for only a small fraction of the total energy injected (typically a few × 10−3). The γ-ray emission is dominated by inverse Compton scattering off the infrared photons of the ISRF. A broken power-law distribution function for the injected particles reproduces the observed spectrum well, except for G0.9+0.1. For G0.9+0.1, we do not need a low-energy counterpart because adiabatic losses alone are enough to reproduce the radio observations. High-energy power-law indices at injection are similar (2.5–2.6), while low-energy power-law indices range from 1.0 to 1.6. The lower limit of the particle injection rate indicates that the pair multiplicity is larger than 104. The corresponding upper limit of the bulk Lorentz factor of the pulsar winds is close to the break energy of the broken power-law injection, except for Kes 75. The initial rotational energy and the magnetic energy of the pulsars seem anticorrelated, although the statistics are poor.