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arXiv 1809.09054astro-ph.HEphysics.plasm-ph
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考虑粒子扩散后反应的脉冲星风星云外流和发射模型

Outflow and Emission Model of Pulsar Wind Nebulae with the Back-reaction of Particle Diffusion

Wataru Ishizaki, Katsuaki Asano, Kyohei Kawaguchi

摘要:

提出了一个新的脉冲星风星云模型,该模型以自洽的方式求解了非热粒子的平流和扩散,以满足动量和能量守恒定律。假设球对称(1-D)稳定外流,我们计算了整个星云的发射光谱积分和表面亮度的径向轮廓。我们发现,粒子扩散的反作用修改了流动剖面。光子谱和表面亮度分布与不考虑粒子扩散反作用的模型计算结果不同。我们的模型被应用到两个良好的研究PWNe 3C 58和G21.5-0.9。通过拟合这些PWNe的光谱,我们确定了参数集,并计算了X射线表面亮度的径向轮廓。对于这两个对象,获得的X射线表面亮度和光子指数的配置文件是很好地与观测一致。我们的模型表明,从星云逃逸的粒子对伽马射线通量有很大的贡献。在我们的模型中预测了一个比射电星云大的$γ$射线晕。

英文摘要:

We present a new pulsar wind nebula (PWN) model solving both advection and diffusion of non-thermal particles in a self-consistent way to satisfy the momentum and energy conservation laws. Assuming spherically symmetric (1--D) steady outflow, we calculate the emission spectrum integrating over the entire nebula and the radial profile of the surface brightness. We find that the back reaction of the particle diffusion modifies the flow profile. The photon spectrum and the surface brightness profile are different from the model calculations without the back reaction of the particle diffusion. Our model is applied to the two well-studied PWNe 3C 58 and G21.5-0.9. By fitting the spectra of these PWNe, we determine the parameter sets and calculate the radial profiles of X-ray surface brightness. For both the objects, obtained profiles of X-ray surface brightness and photon index are well consistent with observations. Our model suggests that particles escaped from the nebula significantly contribute to the gamma-ray flux. A $γ$-ray halo larger than the radio nebula is predicted in our model.

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