Abstract:
Fast Radio Bursts (FRB) are one of the most intriguing transient
phenomena discovered in the recent years, and recently observed down
to 100-MHz frequencies. I will present the first southern hemisphere
all-sky real-time imaging and radio-transient monitoring system,
implemented on two prototype stations of the low frequency (50--350
MHz) component of the Square Kilometre Array (SKA-Low), the
Engineering Development Array 2 (EDA2) and Aperture Array Verification
System 2 (AAVS2). For the last two years these prototypes have been
regularly collecting data to verify their performance against the
SKA-Low specifications and simulations, including making all-sky
images every two seconds used for transient searches. The transient
identification algorithm used 2-second difference images to find
candidates and required their detection in the images from both
stations. In approximately 360 hours of data using a single coarse
channel (0.926 MHz bandwidth), we identified a few episodes of
extremely bright pulses from the pulsar PSR B0950+08 and several
transients from an unknown object, which is currently under
investigation. We also determined preliminary upper limits on surface
density of radio transients at a 2-second timescale. We plan to
increase the bandwidth by at least 40 times (to about 40 MHz) and time
resolution to 10 ms or better in order to improve the sensitivity by
two orders of magnitude and start detecting hundreds of FRBs per
year. This upgrade will transform the stations into low-frequency FRB
survey machines looking for FRBs and signals from extraterrestrial
intelligence in high-resolution all-sky images, which will pave the
way to similar searches with hundreds of SKA-Low stations.
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