In:
Publications of the Astronomical Society of Australia, Cambridge University Press (CUP), Vol. 32 ( 2015)
Kurzfassung:
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.
Materialart:
Online-Ressource
ISSN:
1323-3580
,
1448-6083
DOI:
10.1017/pasa.2015.26
Sprache:
Englisch
Verlag:
Cambridge University Press (CUP)
Publikationsdatum:
2015
ZDB Id:
2560489-2
ZDB Id:
2079225-6
SSG:
16,12
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