Magnetization of the IGM: Role of starburst dwarf galaxies

随着LOFAR的投入使用，存在着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射电同步辐射以及星系团中的法拉第旋转都表明IGM和ICM被一个弱磁场所弥漫，沿着着相对论性粒子。粒子和场都必须由活动星系核（AGN）或正常的恒星形成星系注入IGM。后者的最佳候选者是星暴矮星系，在等级结构形成的框架中，它们必须大量存在。如果这是真的，人们应该能够在局部星暴或星暴后的矮星系周围探测到以前高度相对论性粒子的扩展同步加速器晕。有了LOFAR，我们至少可以找到昏迷星团和更远的地方。

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.