The SKA-Low telescope will be built at
located at the Murchison Radio-astronomy Observatory in Western Australia.
In preparation, several Aperture Array Verification System (AAVS)
testbeds have been constructed on-site to evaluate the performance
of antennas before construction of the full SKA-Low commences.
SKA-Low will cover the frequency range 50 to 350 MHz. One of the main science experiments is to
observe neutral hydrogen in the very early Universe -- the Epoch of Reionisation.
Due to the expansion of the Universe, emission from neutral hydrogen at 1420MHz at this epoch
has been red-shifted to frequencies below 100 MHz. The sensitivity required
to detect such a weak signal at these
frequencies requires a very large collecting area in order to overcome
the high sky brightness temperatures below ~150MHz.
The most practical way to achieve this is by using large number of phased array antennas.
The requirements for SKA-Low include: high sensitivity, excellent polarization performance, the ability to
observe down to zenith angles of 45 degrees, low receiver noise above 150MHz, stability and
affordable cost and power usage.
The image above shows a close-up of the
SKALA antennas in the AAVS1.5 testbed. (Image credit: ICRAR)
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