论文标题
去极化的中间星系对背景无线电发射的影响I.全局磁盘磁场
Effects of Depolarizing Intervening Galaxies on Background Radio Emission I. Global Disk Magnetic Field
论文作者
论文摘要
外部星系通常会在背景无线电源前进行干预，例如类星体和射电星系。背景发射的线性极化被中间星系中不均匀磁化等离子体的法拉第旋转去极化。探索去极化的中间星系（DING）可以是研究银河磁场的宇宙学演化的强大工具。在本文中，我们使用理论叮当模型研究了DING对背景无线电排放的影响。我们发现，星系的复杂结构会导致复杂的去极化特征和法拉第分散函数（FDF），但是对于去极化和FDF的特征，磁场的全局成分很重要。我们显示了银河磁盘中的环磁场的最简单结果。我们发现，去极化的程度显着取决于倾斜角度和丁的影响参数。我们发现标准偏差越大，会发生去极化的可能性就越大。 FDF表示光束内的RM结构。 FDF表现出主要是由于梁内的RM结构以及覆盖背景发射的滴度的比例（填充因子）。 FDF的峰值深度与叮叮束的束平均RM不同。蒙特 - 卡洛模拟表明，丁对观察到的RMS的标准偏差的贡献遵循$σ_ {\ rm rm rm} \ propto 1/{（（1+z）^k} $，带有$ k \ sim 2.7 $，并表现出比波浪长的陡峭的红移依赖。 DING将对未来调查项目（例如SKA和SKA前体/探路者）创建的RM目录产生重大影响。
External galaxies often intervene in front of background radio sources such as quasars and radio galaxies. Linear polarization of the background emission is depolarized by Faraday rotation of inhomogeneous magnetized plasma of the intervening galaxies. Exploring the depolarizing intervening galaxies (DINGs) can be a powerful tool to investigate the cosmological evolution of the galactic magnetic field. In this paper, we investigate the effects of DINGs on background radio emission using theoretical DING models. We find that complex structures of galaxy result in complicated depolarization features and the Faraday dispersion functions (FDFs), but, for the features of depolarizations and FDFs, the global component of magnetic fields is important. We show the simplest results with ring magnetic field in the galactic disk. We find that the degree of depolarization significantly depends on the inclination angle and the impact parameter of the DING. We found that the larger the standard deviation, the more likely it is that depolarization will occur. The FDF represents the RM structure within the beam. The FDF exhibits multi-components due mainly to the RM structure within the beam and the fraction of the DING that covers the background emission (the filling factor). The peak Faraday depth of the FDF is different from the beam-averaged RM of the DING. The Monte-Carlo simulations indicate that DING's contribution to the standard deviation of observed RMs follows $σ_{\rm RM} \propto 1/{(1+z)^k}$ with $k \sim 2.7$ and exhibits a steeper redshift dependence than the wavelength squared. DINGs will have a significant impact on RM catalogs created by future survey projects such as the SKA and SKA Precursor/Pathfinder.
