由巨型射电星系探测的星系际磁场
摘要
宇宙学模拟预言星系际磁场(IGMF)弥漫于宇宙的大尺度结构(LSS)。测量IGMF对确定其起源(即原初或非原初)十分重要。利用LOFAR两米巡天(LoTSS)数据，我们呈现了红移、尺度3.38 Mpc的巨型射电星系J1235+5317的法拉第旋转量(RM)与去偏振性质。我们发现两瓣间平均RM差为 rad/m，此外有~0.1 rad/m的小尺度RM涨落。基于本地宇宙光学光谱观测的LSS纤维状结构星表，我们发现仅指向一瓣视线处有纤维状结构交截的过剩。将整个RM差归因于这些LSS纤维状结构，得到气体密度加权平均IGMF强度约0.3 {\mu}G。然而，与LSS纤维状结构RM贡献的宇宙学模拟直接比较显示，在IGMF强度10至50 nG情形下，RM贡献达2.5 rad/m的概率很低(~5%)。银河系RM涨落(11'尺度上)很可能显著贡献于平均RM差，需更密RM网格以更好约束该贡献。总体而言，本工作展示了LOFAR望远镜探测IGMF微弱特征之潜力。未来研究借助LoTSS数千具高精度RM的源，将能对IGMF性质给出更严苛约束。
引用
@article{arxiv.1811.07934,
title = {The intergalactic magnetic field probed by a giant radio galaxy},
author = {S. P. O'Sullivan and J. Machalski and C. L. Van Eck and G. Heald and M. Brueggen and J. P. U. Fynbo and K. E. Heintz and M. A. Lara-Lopez and V. Vacca and M. J. Hardcastle and T. W. Shimwell and C. Tasse and F. Vazza and H. Andernach and M. Birkinshaw and M. Haverkorn and C. Horellou and W. L. Williams and J. J. Harwood and G. Brunetti and J. M. Anderson and S. A. Mao and B. Nikiel-Wroczynski and K. Takahashi and E. Carretti and T. Vernstrom and R. J. van Weeren and E. Orru and L. K. Morabito and J. R. Callingham},
journal= {arXiv preprint arXiv:1811.07934},
year = {2019}
}
备注
12 pages, 6 figures, 3 tables. This paper is part of the LOFAR surveys data release 1 and has been accepted for publication in a special edition of A&A that will appear in Feb 2019, volume 622. The catalogues and images from the data release will be publicly available on lofar-surveys.org upon publication of the journal