Magnetization of the IGM: Role of starburst dwarf galaxies

随着LOFAR开始运作，有一个很好的机会来阐明一个具有宇宙学意义的问题。与任何明显的离散源无关的漫射同步辐射以及星系团中的法拉第旋转都表明，IGM和ICM伴随着一群相对论粒子而弥漫着弱磁场。粒子和场都必须是由活动星系核(AGN)或正常恒星形成星系注入到IGM中的。后者的最佳候选者是恒星爆发型矮星系，在分级结构形成的框架下，它们肯定存在于大量星系中。如果这是真的，人们应该能够探测到本地星暴或星暴后矮小星系周围先前高度相对论粒子的扩展同步加速器光晕。有了LOFAR，我们至少可以找到昏迷星系团甚至更远的地方。

With LOFAR becoming operational, a great opportunity exists to shed light on a problem of cosmological significance. Diffuse radio synchrotron emission not associated to any obvious discrete sources as well as Faraday rotation in clusters of galaxies both indicate that the IGM and ICM are pervaded by a weak magnetic field, along with a population of relativistic particles. Both particles and fields must have been injected into the IGM either by Active Galactic Nuclei (AGN) or by normal star-forming galaxies. Excellent candidates for the latter are starburst dwarf galaxies, which in the framework of hierarchical structure formation must have been around in large numbers. If this is true, one should be able to detect extended synchrotron haloes of formerly highly relativistic particles around local starburst or post-starburst dwarf galaxies. With LOFAR, we can find these out to at least the Coma Cluster and beyond.