EDA2 159 MHz All-Sky Radio Maps

We present two 159 MHz all-sky maps as product from the all-sky spherical harmonic transit interferometric survey performed with the Engineering Development Array 2 (EDA2). The maps are created with a maximum angular resolution of 3.1 degrees and are systematic bias and noise corrected. These maps have < 0.5 K measured thermal noise and are super sampled on a 0.91-degree pixel grid. One map consists out of purely EDA2 data, covering the sky < 60 degrees in declination, with a global sky component of 247 K added to account for the missing largest scale. The other map covers the whole sky and is prior fit with a rescaled version of the 408 MHz reprocessed desourced and destriped Haslam map (Remazeilles et al. 2015) smoothed to the EDA2 angular resolution. The maps have been created using the m-mode formalism. Along with the sky maps, we also provide a spectral index map calculated relative to the reprocessed Haslam map at 408 MHz and a total intensity noise map.

本研究基于工程开发阵列2（Engineering Development Array 2，EDA2）开展的全天球谐过境干涉测量巡天，生成了两幅159 MHz的全天射电地图。该系列地图均经过系统偏差与噪声校正，最大角分辨率为3.1度；其测量热噪声低于0.5开尔文，并在0.91度的像素网格上完成超采样处理。其中一幅地图仅采用EDA2原始数据构建，覆盖赤纬不超过60度的天区，并添加了247开尔文的全天本底分量以补偿缺失的大尺度信号。另一幅地图覆盖全天天区，以经重标度的408 MHz再处理去点源与去条带版Haslam地图（Haslam map，Remazeilles等，2015）作为先验进行拟合，并将其平滑至与EDA2匹配的角分辨率。上述地图均采用m模式形式体系（m-mode formalism）构建。随本次发布的全天射电图一同提供的，还有以408 MHz再处理版Haslam地图为参照计算得到的谱指数地图，以及总强度噪声地图。