使用LOFAR对木星辐射带低至127 MHz的成像
地球与行星天体物理
2016-02-17 v1 天体物理仪器与方法
摘要
背景。从地球观测木星的同步辐射至今仍是审视绕行星磁捕获的超高能电子分布与动力学行为的唯一方法（因为原位粒子数据在内磁层受限）。目的。我们利用LOFAR在127 MHz上对同步辐射进行了首次高分辨低频成像。该辐射来自低能电子（~1-30 MeV），它们描绘了木星内磁层的广阔区域。方法（完整摘要见原文）结果。获得了127-172 MHz下木星辐射带的首次高分辨图像以及总积分通量密度。它们与先前更高频率的观测相比较，显示出同步辐射源更大的延展（>=4 ）。测量了东西发射峰的不对称性和动态，并存在位于lambda_III=230 {\deg} 25 {\deg}的热斑。谱通量密度测量值处于先前（未分辨）测量值的低侧，暗示低频转折和/或发射谱的时间变化。结论。LOFAR是一个强大且灵活的行星成像仪。127 MHz的观测描绘了延展达约4-5个行星半径的发射。与高频结果的相似性强化了以下结论：i）磁场形态主要塑造了发射的亮度分布；ii）辐射电子可能在约2 内部径向和纬度向分布。尽管如此，亮度的更大延展结合整体更低的通量密度，给出了关于木星电子分布的新信息，这可能阐明这些粒子的起源与输运模式。
引用
@article{arxiv.1511.09118,
title = {Imaging Jupiter's radiation belts down to 127 MHz with LOFAR},
author = {J. N. Girard and P. Zarka and C. Tasse and S. Hess and I. de Pater and D. Santos-Costa and Q. Nenon and A. Sicard and S. Bourdarie and J. Anderson and A. Asgekar and M. E. Bell and I. van Bemmel and M. J. Bentum and G. Bernardi and P. Best and A. Bonafede and F. Breitling and R. P. Breton and J. W. Broderick and W. N. Brouw and M. Brüggen and B. Ciardi and S. Corbel and A. Corstanje and F. de Gasperin and E. de Geus and A. Deller and S. Duscha and J. Eislöffel and H. Falcke and W. Frieswijk and M. A. Garrett and J. Grießmeier and A. W. Gunst and J. W. T. Hessels and M. Hoeft and J. Hörandel and M. Iacobelli and E. Juette and V. I. Kondratiev and M. Kuniyoshi and G. Kuper and J. van Leeuwen and M. Loose and P. Maat and G. Mann and S. Markov and R. McFadden and D. McKay-Bukowski and J. Moldon and H. Munk and A. Nelles and M. J. Norden and E. Orru and H. Paas and M. Pandey-Pommier and R. Pizzo and A. G. Polatidis and W. Reich and H. Röttgering and A. Rowlinson and D. Schwarz and O. Smirnov and M. Steinmetz and J. Swinbank and M. Tagger and S. Thoudam and M. C. Toribio and R. Vermeulen and C. Vocks and R. J. van Weeren and R. A. M. J. Wijers and O. Wucknitz},
journal= {arXiv preprint arXiv:1511.09118},
year = {2016}
}
备注
10 pages, 12 figures, accepted for publication in A&A (27/11/2015) - abstract edited because of limited characters