Multi-beam image offers sneak peek of ASKAP field-of-view
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8 April 2013
CSIRO's ASKAP team has successfully produced the first multi-beam image ever made using phased array feeds (known as PAFs or radio cameras) on an interferometer.
The image, captured as part of the early ASKAP telescope commissioning process, was created with three ASKAP antennas, each fitted with an innovative PAF receiver and associated hardware. Three separate beams were created for each PAF and lined up to track an elongated patch of sky over a 12 hour observation.
This field was specifically chosen to contain a trio of strong and well-known extragalactic sources, with suitable angular separations, including the three brightest points in the image (from top left) PKS 1610-771, PKS 1606-772, PKS 1549-790 and PKS 1547-795.
Importantly, these sources are too far apart to be observed simultaneously using a single pixel feed on a 12-m dish (the size of a single ASKAP antenna). This is a striking demonstration of the power of PAF imaging, particularly given the very limited u-v coverage that three antennas can achieve.
The software correlator used in previous observations was again used in these tests. It correlated the data captured for the three beams simultaneously, with image processing performed in ASKAPsoft, the software custom-designed for the telescope by the ASKAP Computing team.
Now at the MRO, the commissioning team will next look into beam profile measurements, to assess the quality and efficiency of the formed beams.
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