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arXiv 1306.1640astro-ph.HE
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具有非均匀磁场和电子分布的射电星系的同步辐射和逆康普顿辐射

Synchrotron and inverse-Compton emission from radio galaxies with non-uniform magnetic field and electron distributions

M. J. Hardcastle

摘要:

我研究了射电星系扩展结构中的非均匀磁场对观测到的同步辐射和逆康普顿辐射的影响。假设一个各向同性的领域,与一个给定的功率谱和高斯分布的笛卡尔分量的磁场强度,我推导出一个简单的积分,可以用来计算从任何电子人口的同步辐射率。在幂律谱的情况下,我表明,它是可能的,以估计从一个区域的同步辐射率与这样一个领域,并从通常假设的安排,其中$B$是恒定的到处都是,虽然完全纠缠,这种差异是小的,但它增加,如果电子能量密度的规模与字段之间的差异。在这样的场中,老化的电子光谱会产生一个特征性的弯曲同步加速器光谱,该光谱与经典的贾菲-佩罗拉光谱显着不同,我讨论了这可能对标准光谱年龄拟合产生的一些影响。最后,我表明,逆康普顿散射的宇宙微波背景是只有适度的影响,这样的场结构,与效果变得更加重要,如果电子遵循的字段。如果磁场不均匀但各向同性,则文献中来自同步加速器和逆康普顿模型的磁场估计将给出平均磁场能量密度的合理估计。

英文摘要:

I investigate the effect of non-uniform magnetic fields in the extended structures of radio galaxies on the observed synchrotron and inverse-Compton emission. On the assumption of an isotropic field, with a given power spectrum and a Gaussian distribution of the Cartesian components of the magnetic field strength, I derive a simple integral that can be used numerically to calculate the synchrotron emissivity from any electron population. In the case of power-law spectra, I show that it is possible to estimate the difference between the synchrotron emissivity from a region with such a field and that from the commonly assumed arrangement where $B$ is constant everywhere, though fully tangled, and that this difference is small, though it increases if the electron energy density scales with the field. An aged electron spectrum in such a field produces a characteristic curved synchrotron spectrum which differs significantly from the classical Jaffe-Perola spectrum, and I discuss some effects that this might have on standard spectral age fitting. Finally, I show that inverse-Compton scattering of the cosmic microwave background is only moderately affected by such a field structure, with the effects becoming more important if the electrons follow the field. Magnetic-field estimates in the literature from combined synchrotron and inverse-Compton modelling will give reasonable estimates of the mean magnetic field energy density if the field is non-uniform but isotropic.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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