Spectral-Line Observations Using a Phased Array Feed on the Parkes Telescope

Abstract

Copyright © Astronomical Society of Australia 2017 We present first results from pilot observations using a phased array feed (PAF) mounted on the Parkes 64-m radio telescope. The observations presented here cover a frequency range from 1 150 to 1 480 MHz and are used to show the ability of PAFs to suppress standing wave problems by a factor of ~10, which afflict normal feeds. We also compare our results with previous HIPASS observations and with previous H i images of the Large Magellanic Cloud. Drift scan observations of the GAMA G23 field resulted in direct H i detections at z = 0.0043 and z = 0.0055 of HIPASS galaxies J2242-30 and J2309-30. Our new measurements generally agree with archival data in spectral shape and flux density, with small differences being due to differing beam patterns. We also detect signal in the stacked H i data of 1 094 individually undetected galaxies in the GAMA G23 field in the redshift range 0.05 ? z ? 0.075. Finally, we use the low standing wave ripple and wide bandwidth of the PAF to set a 3s upper limit to any positronium recombination line emission from the Galactic Centre of < 0.09 K, corresponding to a recombination rate of < 3.0 × 10 45 s -1 .