Towards a New Era of Observing Cosmic Magnetic Fields

Towards a New Era of Observing Cosmic Magnetic Fields
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DOI：
10.22323/1.112.0003
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发表时间：
2010-09
期刊：
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影响因子：
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通讯作者：
R. Beck
R. Beck
中科院分区：
其他
文献类型：
--
作者：
R. Beck

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宇宙磁场的起源是天体物理学和基础物理学中的一个悬而未决的问题。利用即将到来的大型射电望远镜进行的偏振观测将开启磁场观测的新纪元，并应有助于了解磁场的起源。在低频率下，LOFAR（30 - 240 MHz）将使我们能够绘制星系外围区域和星系晕、星系团和银河系中弱磁场的结构。小的法拉第旋转测量也可以在低频下进行最佳测量。EVLA、MeerKAT和SKA观测到的更高频率（1 - 10 GHz）的偏振将以前所未有的细节追踪附近星系盘和中心区域的磁场。SKA脉冲星巡天将发现许多新的脉冲星;它们的RM将以高精度绘制银河系的磁场。利用SKA及其前身望远镜ASKAP（POSSUM项目）对偏振背景源密集网格进行法拉第旋转测量的全天巡天，专门用于测量遥远的居间星系、星系团和星系间细丝的磁场，并将用于模拟银河系磁场的总体结构和强度。与SKA，大规模的模式，在星系中的规则场可以识别到约100 Mpc的距离，有序的领域在未解决的星系或集群遗迹的红移z ' 0.5，湍流领域在星暴星系或集群晕z ' 3和规则领域在居间星系对类星体z ' 5。
The origin of magnetic fields in the Universe is an open problem in astrophysics and fundamental physics. Polarization observations with the forthcoming large radio telescopes will open a new era in the observation of magnetic fields and should help to understand their origin. At low frequencies, LOFAR (30‐240 MHz) will allow us to map the structure of weak magnetic fields in the outer regions and halos of galaxies, in galaxy clusters and in the Milky Way. Small Faraday rotation measures can also be best measured at low frequencies. Polarization at higher frequencies (1‐10 GHz) as observed with the EVLA, MeerKAT and the SKA will trace magnetic fields in the disks and central regions of nearby galaxies in unprecedented detail. The SKA pulsar survey will find many new pulsars; their RMs will map the Milky Way’s magnetic field with high precision. All-sky surveys of Faraday rotation measures towards a dense grid of polarized background sources with the SKA and its precursor telescope ASKAP (project POSSUM) are dedicated to measure magnetic fields in distant intervening galaxies, clusters and intergalactic filaments, and will be used to model the overall structure and strength of the magnetic field in the Milky Way. With the SKA, large-scale patterns of regular fields in galaxies can be recognized to about 100 Mpc distance, ordered fields in unresolved galaxies or cluster relics to redshifts of z ’ 0.5, turbulent fields in starburst galaxies or cluster halos to z ’ 3 and regular fields in intervening galaxies towards QSOs to z ’ 5.