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arXiv 0803.1403astro-ph
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第谷SNR的内部动力学和粒子加速

Internal dynamics and particle acceleration in Tycho's SNR

H. J. Voelk, E. G. Berezhko, L. T. Ksenofontov

摘要:

对第谷超新星遗迹(SNR)的超新星爆炸能量1.2 × 10 ^{51}尔格的新建议值的结果进行了探讨。利用宇宙线加速的非线性动力学理论,研究了第谷信噪比的性质及其与现有实验数据的对应关系。它表明,大的接触间断和前向激波的半径之间的平均比率是一致的核高能粒子在前向激波的非常有效的加速。同时也指出,要使E_{sn} = 1.2 × 10 ^{51}尔格的值与气体动力学、加速理论和现有的γ射线测量值相一致,则源距应大于3.3 kpc。相应的环境气体数密度低于0.4 cm^{-3}。由于预期的伽马射线通量强烈地依赖于源距离F_γ \propto d^{-7},未来根据第谷信噪比对实际伽马射线通量的实验测定将使确定源距离和平均环境气体密度的值成为可能。一个简单的逆康普顿模型,没有一个占主导地位的人口的核CR是不兼容的目前上限的伽马射线发射任何合理的环境星际B场。考虑到加速理论和整体以及内部气体动力学之间的一致性,未来的伽马射线探测将使第谷SNR中的核粒子加速在我们看来是无可争议的。

英文摘要:

The consequences of a newly suggested value for the SN explosion energy 1.2x10^{51} erg are explored for the case of Tycho's supernova remnant (SNR). A nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs is employed to investigate the properties of Tycho's SNR and their correspondence to the existing experimental data. It is demonstrated that the large mean ratio between the radii of the contact discontinuity and the forward shock is consistent with the very effective acceleration of nuclear energetic particles at the forward shock. It is also argued that consistency of the value E_{sn} = 1.2x10^{51} erg with the gas dynamics, acceleration theory, and the existing gamma-ray measurements requires the source distance to be greater than 3.3 kpc. The corresponding ambient gas number density is lower than 0.4 cm^{-3}. Since the expected gamma-ray flux strongly depends on the source distance, F_γ\propto d^{-7}, a future experimental determination of the actual gamma-ray flux from Tycho's SNR will make it possible to determine the values of the source distance and of the mean ambient gas density. A simple inverse Compton model without a dominant population of nuclear CRs is not compatible with the present upper limit for the gamma-ray emission for any reasonable ambient interstellar B-field. Given the consistency between acceleration theory and overall, as well as internal, gas dynamics, a future gamma-ray detection would make the case for nuclear particle acceleration in Tycho's SNR incontrovertible in our view.

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