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arXiv 1103.0909astro-ph.HE
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Markarian 421中发射电子的环境和分布与源活动的关系

The environment and distribution of emitting electrons as a function of source activity in Markarian 421

Nijil Mankuzhiyil, Stefano Ansoldi, Massimo Persic, Fabrizio Tavecchio

摘要:

对于高频峰值BL Lac对象Mrk 421,我们研究的光谱能量分布(SED)的变化作为源活动的函数,从静态到活动。我们使用一个完全自动化的卡方最小化程序,而不是“眼球”的过程中更常用的文献中,九个SED数据集与一个区域同步自康普顿(SSC)模型和研究模型参数如何随源活动。后一个问题现在终于可以解决了,因为同时宽带SED(从光学到VHE光子能量)终于变得可用。我们的研究结果表明,在Mrk 421的磁场减少与源活动,而电子谱的断裂能和多普勒因子增加-其他SSC参数原来是不相关的源活动。在SSC的框架中,这些结果被解释在一个图片中,同步功率和峰值频率保持恒定与不同的源活动,通过降低磁场和增加的电子数密度低于断裂能量的组合:由于这导致增加的电子-光子散射效率,所产生的康普顿功率增加,所以总(=同步加康普顿)发射。

英文摘要:

For the high-frequency peaked BL Lac object Mrk 421 we study the variation of the spectral energy distribution (SED) as a function of source activity, from quiescent to active. We use a fully automatized chi-squared minimization procedure, instead of the "eyeball" procedure more commonly used in the literature, to model nine SED datasets with a one-zone Synchrotron-Self-Compton (SSC) model and examine how the model parameters vary with source activity. The latter issue can finally be addressed now, because simultaneous broad-band SEDs (spanning from optical to VHE photon energies) have finally become available. Our results suggest that in Mrk 421 the magnetic field decreases with source activity, whereas the electron spectrum's break energy and the Doppler factor increase -- the other SSC parameters turn out to be uncorrelated with source activity. In the SSC framework these results are interpreted in a picture where the synchrotron power and peak frequency remain constant with varying source activity, through a combination of decreasing magnetic field and increasing number density of electrons below the break energy: since this leads to an increased electron-photon scattering efficiency, the resulting Compton power increases, and so does the total (= synchrotron plus Compton) emission.

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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