Measurements of Cosmic Magnetism with LOFAR and SKA

[摘要] The origin of magnetic fields in stars, galaxies and clusters is anopen problem in astrophysics. The next-generation radio telescopesLow Frequency Array (LOFAR) and Square Kilometre Array(SKA) will revolutionize the study of cosmic magnetism. "Theorigin and evolution of cosmic magnetism" is a key science projectfor SKA. The planned all-sky survey of Faraday rotation measures(RM) at 1.4 GHz will be used to model the structure and strength ofthe magnetic fields in the intergalactic medium, the interstellarmedium of intervening galaxies, and in the Milky Way. Acomplementary survey of selected regions at around 200 MHz isplanned as a key project for LOFAR. Spectro-polarimetryapplied to the large number of spectral channels available for LOFARand SKA will allow to separate RM components from distinctforeground and background regions and to perform 3-D Faradaytomography of the interstellar medium of the Milky Way and nearbygalaxies. – Deep polarization mapping with LOFAR and SKA will opena new era also in the observation of synchrotron emission frommagnetic fields. LOFAR's sensitivity will allow to map the structureof weak, extended magnetic fields in the halos of galaxies, ingalaxy clusters, and possibly in the intergalactic medium.Polarization observations with SKA at higher frequencies (1–10 GHz)will show the detailed magnetic field structure within the disks andcentral regions of galaxies, with much higher angular resolutionthan present-day radio telescopes.

[学科分类] 电子、光学、磁材料