GLEAM: The GaLactic and Extragalactic All-Sky MWA Survey
GLEAM: The GaLactic and Extragalactic All-Sky MWA Survey
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DOI：
10.1017/pasa.2015.26
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发表时间：
2015-05
影响因子：
6.3
通讯作者：
R. Wayth;E. Lenc;M. Bell;J. Callingham;J. Callingham;K. Dwarakanath;T. Franzen;B. For;B. Gaensler-B
中科院分区：
文献类型：
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作者：
R. Wayth;E. Lenc;M. Bell;J. Callingham;J. Callingham;K. Dwarakanath;T. Franzen;B. For;B. Gaensler-B
摘要GLEAM，银河系和银河系外全天空MWA巡天，是在72和231 MHz之间的频率上对10 ° +25 °以南的整个无线电天空进行的巡天，使用MWA使用漂移扫描方法，有效地利用MWA的非常大的视场。我们提出的观察细节，成像策略，和理论灵敏度GLEAM。调查持续了两年，第一年使用40 kHz频率分辨率和0.5 s时间分辨率;第二年使用10 kHz频率分辨率和2 s时间分辨率。所得到的图像分辨率和灵敏度取决于观测频率、天空指向和图像加权方案。在154 MHz时，图像分辨率约为2.5 × 2.2/cos（δ + 26.7°）arcmin，对角尺寸高达~ 10°的结构具有灵敏度。我们提供的表格来计算预期的热噪声GLEAM马赛克取决于指向和频率，并讨论了限制，以实现斯托克斯我的图像的理论噪声。我们讨论的挑战，以及他们的解决方案，出现GLEAM包括电离层对源位置和线性极化发射的影响，以及固有的MWA的主光束的仪器极化效应。
Abstract GLEAM, the GaLactic and Extragalactic All-sky MWA survey, is a survey of the entire radio sky south of declination + 25° at frequencies between 72 and 231 MHz, made with the MWA using a drift scan method that makes efficient use of the MWA’s very large field-of-view. We present the observation details, imaging strategies, and theoretical sensitivity for GLEAM. The survey ran for two years, the first year using 40-kHz frequency resolution and 0.5-s time resolution; the second year using 10-kHz frequency resolution and 2 s time resolution. The resulting image resolution and sensitivity depends on observing frequency, sky pointing, and image weighting scheme. At 154 MHz, the image resolution is approximately 2.5 × 2.2/cos (δ + 26.7°) arcmin with sensitivity to structures up to ~ 10° in angular size. We provide tables to calculate the expected thermal noise for GLEAM mosaics depending on pointing and frequency and discuss limitations to achieving theoretical noise in Stokes I images. We discuss challenges, and their solutions, that arise for GLEAM including ionospheric effects on source positions and linearly polarised emission, and the instrumental polarisation effects inherent to the MWA’s primary beam.