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13th of May 2020
PKS B1934-638
by Heywood et al.
The radio source PKS B1934-638 is a Giga-hertz Peaked Spectrum source that is widely used a primary calibrator source for radio interferometers in the southern hemisphere, as it is extremely stable, compact, and effectively unpolarized. Observations with radio interfereometers will usually include an observation of PKS B1934-638 to be used for flux density and bandpass calibration. However, the wide field-of-view and high sensitivity of modern interferometers means that additional sources are often also detected, which can introduce errors into bandpass corrections and subsequently the target data if not properly accounted for. The impact of this has recently been studied by Heywood et al., who have considered the cases of ASKAP, MeerKAT, and Band 2 of SKA-MID.

The image above shows the radio spectrum of PKS B1934-638 derived from the 1994 Reynolds model. The solid blue curve shows the frequency extent over which measurements were used to derive the polynomial fit to the spectrum, and the dashed line shows the extrapolation of the spectrum using that polynomial. Also marked on the figure are the frequency ranges of ASKAP (0.7–1.9 GHz), MeerKAT’s UHF (0.58–1.05 GHz) and L-band (0.87–1.67 GHz) receivers, and the assumed ranges of Bands 1 (0.35–1.05 GHz) and 2 (0.95–1.76 GHz) of SKA-MID. More details are given in the paper, published in Monthly Notices of the Royal Astronomical Society.

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