标题： MWA长基线再电离时代调查：I. EoR 0区域的改进源目录 显示英文标题

标题： The MWA Long Baseline Epoch of Reionisation Survey: I. Improved Source Catalogue for the EoR 0 field

摘要： 对再电离时期(EoR)实验的主要系统性限制之一是前景校准模型的准确性。最近的结果表明，为了减少前景功率，需要对扩展前景源进行高精度建模，并包括主波束及其旁瓣中的源的模型。为了提高由默奇森宽场阵列(MWA)观测的EoR区域的源模型的准确性，我们进行了MWA长基线再电离时期调查(LoBES)。该调查使用MWA第二阶段扩展阵列对主要MWA EoR区域及其八个相邻区域进行多频段观测。我们展示了以MWA EoR0观测区域为中心的调查前半部分的结果（中心位于RA(J2000) 0 h，Dec(J2000) -27 deg）。这一部分的调查覆盖了3069度$^2$的区域，平均均方根为2.1 mJy beam$^{-1}$。该目录总共包含80824个源，在100到230 MHz之间有16次独立的光谱测量，并且对其中的78$\%$个源进行了光谱建模。在该区域内，我们估计目录在32 mJy时的完整性为90$\%$，在10.5~mJy时的完整性为70$\%$。总体归一化源计数与类似灵敏度的先前低频调查结果一致。测试新源模型的性能，我们在一组MWA第一阶段数据中测得剥离源的残差均方根值较低，尤其是对扩展源而言。这些数据残差的二维功率谱也显示出在小角尺度上的改进——这与LoBES目录更好的角分辨率一致。很明显，LoBES天空模型优于澳大利亚MWA EoR小组用于EoR0区域的当前天空模型。 显示英文摘要

摘要： One of the principal systematic constraints on the Epoch of Reionisation (EoR) experiment is the accuracy of the foreground calibration model. Recent results have shown that highly accurate models of extended foreground sources, and including models for sources in both the primary beam and its sidelobes, are necessary for reducing foreground power. To improve the accuracy of the source models for the EoR fields observed by the Murchison Widefield Array (MWA), we conducted the MWA Long Baseline Epoch of Reionisation Survey (LoBES). This survey consists of multi-frequency observations of the main MWA EoR fields and their eight neighbouring fields using the MWA Phase II extended array. We present the results of the first half of this survey centred on the MWA EoR0 observing field (centred at RA(J2000) 0 h, Dec(J2000) -27 deg). This half of the survey covers an area of 3069 degrees$^2$, with an average rms of 2.1 mJy beam$^{-1}$. The resulting catalogue contains a total of 80824 sources, with 16 separate spectral measurements between 100 and 230 MHz, and spectral modelling for 78$\%$ of these sources. Over this region we estimate that the catalogue is 90$\%$ complete at 32 mJy, and 70$\%$ complete at 10.5~mJy. The overall normalised source counts are found to be in good agreement with previous low-frequency surveys at similar sensitivities. Testing the performance of the new source models we measure lower residual rms values for peeled sources, particularly for extended sources, in a set of MWA Phase I data. The 2-dimensional power spectrum of these data residuals also show improvement on small angular scales -- consistent with the better angular resolution of the LoBES catalogue. It is clear that the LoBES sky models improve upon the current sky model used by the Australian MWA EoR group for the EoR0 field.