Title: Direction-Dependent Polarised Primary Beams in Wide-Field Synthesis Imaging Show Chinese title

Title: 宽场综合成像中的方向依赖偏振初级波束

Abstract: The process of wide-field synthesis imaging is explored, with the aim of understanding the implications of variable, polarised primary beams for forthcoming Epoch of Reionisation experiments. These experiments seek to detect weak signatures from redshifted 21cm emission in deep residual datasets, after suppression and subtraction of foreground emission. Many subtraction algorithms benefit from low side-lobes and polarisation leakage at the outset, and both of these are intimately linked to how the polarised primary beams are handled. Building on previous contributions from a number of authors, in which direction-dependent corrections are incorporated into visibility gridding kernels, we consider the special characteristics of arrays of fixed dipole antennas operating around 100-200 MHz, looking towards instruments such as the Square Kilometre Array (SKA) and the Hydrogen Epoch of Reionization Arrays (HERA). We show that integrating snapshots in the image domain can help to produce compact gridding kernels, and also reduce the need to make complicated polarised leakage corrections during gridding. We also investigate an alternative form for the gridding kernel that can suppress variations in the direction-dependent weighting of gridded visibilities by 10s of dB, while maintaining compact support. Show Chinese abstract

Abstract: 宽视场综合成像过程被探讨，旨在理解可变的、偏振的主要波束对即将进行的再电离时代实验的影响。 这些实验试图在抑制和减去前景辐射后的深层残差数据集中检测红移21厘米发射的微弱信号。 许多减法算法从一开始就受益于低旁瓣和偏振泄露，这两者都与如何处理偏振主要波束密切相关。 在前人工作的基础上，我们考虑了固定偶极子天线阵列在100-200 MHz频段的特殊特性，这些工作将方向相关的校正纳入到可见度栅格化内核中，面向诸如平方公里阵列（SKA）和再电离时代的氢气阵列（HERA）等仪器。 我们展示了在图像域中集成快照可以帮助生成紧凑的栅格化内核，并且还可以减少在栅格化过程中进行复杂的偏振泄露校正的需求。 我们还研究了栅格化内核的一种替代形式，这种形式可以将栅格化可见度的方向相关权重变化抑制数十分贝，同时保持紧凑的支持。